BE483916A - - Google Patents

Description

       

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  Telephone system with power line connections
The present invention relates to telephone systems, and more particularly to those of the automatic long-distance-to-long-distance type using carrier current paths or links.



   One of the general aims of the invention is to obtain an automatic long distance to long distance system comprising a network of central offices and automatic offices provided with subscriber stations, prepaid stations, manual and automatic switchboards, and wherein the usual medium-distance or regional and long-distance or trunk communications can be established and monitored using the powerline links.



   Another object of the invention is to obtain a telephone system comprising a remote exchange of the automatic type, a tandem exchange of the automatic type and a main office provided with a switchboard, and an improved device for establishing communications connecting the central stations to the main office switchboard.



   Another object of the invention is to obtain, in a telephone system of the type described, an improved device allowing

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 both to establish communications between the stations of the central offices and the switchboard of the main office, and comprising a first set of power line links between the centers and a second set of power line links between the central and the main office , which allows communications passing through the main office switchboard to be kept under absolute surveillance.



   The object of the invention is also to obtain, in a telephone system of the type described, an improved device allowing calls to be made freely from the stations of the various exchanges, to the switchboard of the main office, and to establish the charges relating to communications between the sets of the various exchanges.



   Yet another object of the invention is to obtain, in a telephone system of the type described, an improved device for blocking calls originating from the stations of the remote exchange and intended for the stations of the tandem exchange when the routing. outgoing station chosen is the one normally used to route calls from stations in the remote exchange to the switchboard in the main office, through the automatic switching devices of the transit exchange.



   Another object of the invention is to obtain, in a telephone system of the type described, an improved device. both to freely initiate the calls indicated above, to establish the charges relating to the conversations in question and to block the calls defined above, whether the remote exchange sets where the calls originate, or of the "telephone set" type. 'subscribers' or of the 'prepaid set' type.



   The invention also envisages obtaining a telephone system comprising an exchange connected to an unattended repeater. and a main office connected to said repeater by a powerline carrier link, an improved device allowing automatic verification of the operating conditions of the carrier current link and the triggering of a signal to

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 main office in this case this oeiecLous conaitions to said liaison.



   Another object of the invention is to obtain, in a telephone system comprising two main offices linked together by a powerline link and each provided with stations, a switchboard and automatic switching devices, an improved device enabling the switchboard of one of said main offices to control, via the power line link, the switching devices of the other main office, so that communications can be made. be routed from the switchboard of one of the main offices and selectively to the stations and switchboard of the other main office.



   The invention further contemplates obtaining, in a telephone system comprising a first main office provided with a manual switch panel and a second main office fitted with an automatic switch panel, an improved device allowing '' establish communication by means of a powerline link and automatic switching devices, between the manual switch panel and the automatic switch panel, a delayed dialing pulse being transmitted from the switching devices. switching, via the carrier current link, to the manual switch board in the event that a certain time interval is required for the switching devices to perform an operation after receiving a determined figure.



   Another object of the invention is to obtain, in a telephone system comprising a first main office provided with an automatic switchboard and a second main office fitted with a manual switchboard, an improved device comprising a recorder-transmitter capable of be controlled from the trunk switchboard for automatic switching to establish a communication from said switchboard, passing through a carrier current link and terminating at the switching board.

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 manual dialer, a delayed dial pulse being returned by the switching devices and via the powerline carrier link to the recorder-transmitter,

   so as to control its transmissions in the event that a certain time interval is necessary for the switching devices to perform an operation after the reception of a determined figure.



   Yet another object of the invention is to obtain, in a telephone system comprising two main offices associated by an interurban or long-distance link, an improved device for establishing a communication between a first switchboard belonging to the 'one of the main offices and a second switchboard belonging to the other main office via the power line link, a system in which the various monitoring pulses necessary to facilitate the flow of long-distance traffic are all transmitted by the carrier current link between the two switch panels.



   Another object of the invention is to obtain, in a telephone system comprising two junction circuits connected by a regional or medium-distance junction, an improved device in which the first junction circuit comprises a source of ordinary battery potential. and a source of surge battery potential and wherein the second junction circuit includes a source of return potential and unbalanced current conducting equipment by means of which communication can be routed between a first line to the first circuit. junction and a second line from the second junction circuit using the elements indicated in the two junction circuits,

   and by means of which monitoring pulses can be transmitted back and forth between the lines, as required.



   The invention also envisages obtaining, in a telephone system comprising two junction circuits connected by a

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 medium-distance junction, of an improved device in which the first junction circuit has a source of ordinary battery potential and a surge battery potential run, and in which the second junction circuit has a source of return potential and equipment that conducts asymmetric current,

   device by means of which communication can be routed between a second line arriving at the second trunk circuit and a first line starting at the first trunk circuit using the elements indicated in the two trunk circuits and by means of which monitoring pulses can be transmitted in one direction or the other between the lines as required.



   Other particularities of the invention relate to the particular arrangement of the circuit elements of the system by means of which the characteristics indicated above and other functional characteristics can be achieved.



   The invention will be better understood on reading the detailed description which will follow and on examining the appended drawings which represent, by way of non-limiting example, an embodiment of said invention.



   Fig. 1 is a schematic representation of an automatic telephony system embodying the invention and comprising a remote exchange 10, a tandem exchange 20, a repeater station 30, a main office 40 and a remote office 50. FIGS. 2 to 10 taken together represent the details of the apparatuses of the automatic telephony system shown in FIG. 1 and embodying the characteristics of the invention, as they have been briefly indicated above. Figures 2 to 10 should * be connected from left to right and edge to edge to form an overall diagram.



   In particular, Figures 2 and 3 show schematically the automatic switching devices and one of the elements of the powerline devices provided at the remote exchange 10, as well as details of one of the junction circuits. this central.

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   Figures 4, 5 and 6 show schematically the automatic switching devices and one of the elements of the powerline devices provided at the tandem exchange 20, as well as the details of two different junction circuits belonging to said tandem exchange.



   FIG. 6 also shows, in achematic form, one of the elements of the powerline devices belonging to the repeater station 30, together with the details of one of the junction circuits of one of the transmitters. 'warning pulses of said station.



   Figure 7 shows schematically one of the elements of the powerline devices provided at main office 40, together with the details of one of the connecting circuits of one of the receivers of the warning pulses and of one of the dicordes of said office.



   Figure 8 shows schematically the automatic switching devices and one of the elements of the powerline devices provided at the main office 40, as well as the details of a junction circuit of said office different from that of figure 7.



   Figures 9 and 10 show schematically the automatic switching devices and one of the elements of the powerline devices provided at the remote office 50, as well as the details of one of the junction circuits of said remote office.
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  THE AUTC! LATICAL TELEPHONE SYSTEM t
We will first of all consider more particularly FIG. 1. The automatic telephony system represented in this figure comprises the remote exchange 10 serving a certain number of ordinary subscriber stations including in particular the subscriber station T11, and a certain number of ordinary subscriber stations. number of prepaid sets including in particular the T12 prepaid set. The subscriber station Tll is connected to a subscriber line 211 which terminates at said station and with which a circuit is individually associated.

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 line 213. The prepayment station T 12 is connected to a line 212 which terminates at said station and with which a line circuit 214 is individually associated.

   the remote exchange 10 further comprises several groups of searcher-selector junctions; the first group includes the search-selector junction 203 and is provided with a distributor 204. The remote exchange further comprises a certain number of urban connector groups, the first group of urban connectors comprising in particular the urban connector 205.

   Preferably, the subscriber line 211 terminating at the subscriber set T 11 and the line 212 terminating at the prepaid set T 12 belong to the first group of lines and are therefore accessible to both the searchers of the first seek-selector junction group. 203, etc .... that to the first group of urban connectors 205, ect ..... In addition, a remote exchange 10 comprises a group of arrival selectors, including in particular the arrival selector 206, which has access to the various groups of urban connectors, the urban connector 205 of the first group being accessible to the arrival selector 206 via the junction 207 which ends at said connector.



   The remote exchange 10 and the tandem exchange 20 are connected by a number of powerline paths. The first channel shown comprises the line 60 connecting the remote exchange 10 to the tandem exchange 20 and terminating respectively on the power line equipment 394 of the remote exchange 10 and on the power line equipment 494 of the tandem exchange 20. .



  Powerline carrier equipment 394 is connected to a junction circuit 200 which is individual to it, provided at the remote exchange 10 said junction circuit 200 is connected by a junction 230 to the incoming selector 206 which belongs to it individually.



  In addition, the junction circuit 200 has two additional junctions 220 & 325, both accessible to the selectors of the different searcher-selector junction groups. Finally, the selectors of the different search-selector junction groups of the remote exchange 10 also have access to the different

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 groups of urban connectors of the said central. In particular, the selector of the researcher-selector junction 203 has access to the urban connector 205, via the junction 207 which ends at said conneoteur.



   The tandem exchange 20 serves a certain number of ordinary subscriber stations comprising in particular the subscriber station T 21 and a certain number of prepaid stations comprising in particular the prepaid station T 22. The subscriber station T 21 is connected. to a subscriber line 421 terminating at said station and comprising a line circuit 423 which is individually associated with it. The prepayment station T 22 is connected to a line 422 terminating at said station and comprising a line circuit 424 which is individually associated with it.

   Likewise, the tandem exchange 20 has a number of seeker-selector junction groups, the first of these groups comprising seeker-selector junction 426 and being provided with a distributor 425, as well as a certain number of junction groups. number of groups of urban connectors, the first of these groups comprising in particular the urban connector 427. Preferably, the subscriber line 421 which ends at the subscriber station T 21 and the line 422 which ends at the station at prepayment T 22 belong to the first group of lines and are, consequently, accessible both to the researcher of the first group of researcher-selector junctions 426, ect ..... and to the first group of urban connectors 427, ect .. ..

   On the other hand, the tandem exchange 20 comprises a first group of arrival selectors comprising in particular the arrival selector 429 and having access to the various groups of urban connectors, and a second group of arrival selectors comprising in particular the selector 434 and having access to the different groups of urban connectors. The urban connector 427 of the first group is accessible to the arrival selectors 429, etc ... and 434, eto .... via the junction 428 leading to said connector. Powerline carrier 494 of the tandem exchange 20 is connected to a junction circuit 400 which

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 belongs to him individually. Said junction circuit 400 is connected by a junction 435 to the arrival selector 429 which belongs to it individually.

   In addition, the junction circuit 400 comprises an additional junction 430 accessible to the selectors of the different groups of seeker-selector junctions and to the group of arrival selectors 434, ect ...



   The tandem exchange 20 and the repeater station 30 are interconnected by a group of trunk lines comprising in particular the trunk line 665, Each of the trunk lines ends with a trunk circuit provided at the tandem exchange 20 and by a junction circuit provided at the repeater station 30. The junction line 665 ends at the junction circuits 500 and 600 belonging respectively to the tandem exchange 20 and to the repeater station 30. The junction circuit 500 is connected by a junction 520 to the arrival selector 434 which belongs to it individually. In addition, the junction circuit 500 has two additional junctions 10 and 515 respectively accessible to the selectors of the different searcher-selector junction groups and to the arrival selectors 429, etc.

   Finally, the selectors of the different gm upas of seeker-selector junctions of the tandem exchange 20 also have access to the different groups of urban connectors of said exchange. In particular, the selector of the finder-selector junction 426 has access to the urban connector 427 via the junction 428 which terminates at the connector.



   Repeater station 30 and main office 40 are connected by a number of powerline lines. The first track shown comprises the line 70 connecting the repeater station 30 to the main office 40 and terminating respectively on the powerline apparatus 649 of the repeater station 30 and on the powerline apparatus 794 of the main office 40.



  Powerline carrier equipment 694 is connected to the junction circuit 600 which is individual to it at repeater station 30. Said

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 Trunk circuit terminates one of the ends of trunk line 665 which connects tandem exchange 20 to repeater station 30, as previously indicated. In addition, a number of warning pulse transmitters 680, etc ... are provided at repeater station 30 and are respectively connected to powerline carrier equipment 694, etc ...



   Powerline carrier equipment 794 in main office 40 is connected to an individual junction circuit 700.



  Said trunk circuit 700 terminates in a J-jack 730 which is located in front of an attendant switch board 765 at main office 40. said attendant board 765 has a number of dicords including dichord 766. In addition, several receivers warning pulses 770, etc ... are provided at main office 40 and are respectively connected to powerline carrier 794, etc ...



   The main office 40 serves a certain number of ordinary subscriber stations including in particular the subscriber station T 41.



  The subscriber station T 41 is associated with a subscriber line 841 which terminates at said station and which comprises a line circuit 842 which is individually associated with it. In addition, the main office 40 includes a train of city switches 844 provided with the distributor 843. The subscriber line 841 which terminates at the subscriber station T 41 'has access to the train of city switches 844 and is accessible to said train. In addition, the main office 40 has a group of direct traffic junctions including in particular the direct traffic junction 846. The direct traffic junction 846 is accessible to the trunk switch train 844 through a junction 845 and further includes a junction 847 which terminates on a J 848 jack disposed in front of the operator switch board 765.

   On the other hand, the main office 40 comprises a train of interurban switches 805 which has access to lines 841, etc ..., respectively terminating at subscriber stations T 41, etc ... Said train of interurban switches 805 comprises - you a junction 806 which leaves from said switches and ends

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 on a jaok J 807 placed in front of the switchboard operator 765. In addition, the main office 40, includes a group of arrival selectors including in particular the arrival selector 812 and having access to the train of interurban switches 805 via junction 806 which terminates at said switches. In addition, the main office 40 has a group of inbound trunk junctions 809, etc.

   The incoming trunk junction 809 is accessible to the arrival selector 812 via the junction 808 which ends at said trunk junction and is provided with a junction 810 which starts from said trunk junction and terminates on a jack J 811 arranged in front of the operator switch panel 765.



   Main office 40 and remote office 50 are connected by a number of powerline lines, the first line shown comprising line 80 which connects main office 40 to remote office 50 and respectively terminating on the switchgear at powerline 894 from main office 40 and 'on powerline 994 from remote office 50.



  Powerline carrier equipment 894 is connected to main office 40 to an individual trunk 800. said junction circuit 800 is connected by a junction 875 to the arrival selector 812 which is individual to it. In addition, the junction circuit 800 terminates on a J 815 jack located in front of the operator switch board 765.



   The remote office 50 serves a certain number of ordinary subscriber stations including in particular the subscriber station T 51 The subscriber station T 51 is connected to a subscriber line 1051 leading to said station and carrying a line circuit. 1052 which is individually associated with it. On the other hand, the remote office 50A comprises a train of city switches 1054 provided with a distributor 1053. The subscriber line 1051 terminating at the subscriber station T 51 has access to the train of local switches 1054 and is accessible above said switches.

   In addition, the remote office 50

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 has a trunk switchboard of the Strowger 1060 type provided with a certain number of interurban operator positions, one of which is indicated in 1061. Each trunk operator position is provided with a group of junctions researcher-selector who is individual to him. The group of individual selector seeker junctions at the long distance operator position 1061 notably comprises the searcher-selector junction 1062. In addition, the remote office 50 comprises a group of direct traffic junctions including in particular the direct traffic junction 1056.



  The direct traffic junction 1056 is accessible to the trunk switch train 1054, via a junction 1055 terminating at said direct traffic junction. The direct traffic junction circuit 1056 further comprises a junction 1057 which leaves from said circuit and which is accessible to seekers of the searcher-selector junctions associated with the different trunk operator positions of the Strowger 1060 automatic trunk switchboard. , the remote office 50 comprises a train of interurban switches 1038 which has access to lines 1051, etc ... respectively terminating at subscriber stations T 51, etc ...

   The trunk switch train 1038 comprises a junction 1037 which terminates at said train and which is accessible to the selectors of the searcher-selector junctions associated with the various long distance operator positions of the Strowger automatic trunk switch 1060. In addition, the remote office 50 comprises a group of arrival selectors comprising in particular the arrival selector 1036 and having access to the train of interurban switches 1038 via the junction 1037 leading to said switches. Remote office 50 still has a group of inbound trunk trunks 1066, etc.

   The incoming interurban junctions 1066, etc ... are accessible to the arrival selector 1036 via a junction 1065 terminating at said interurban junctions and comprising a junction 1067 accessible to the searchers of the junctions.

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 finder-selector functions associated with the different long distance operator positions of the Strowger 1060 automatic long distance switchboard.



   Powerline carrier equipment 994 provided at remote office 50 is connected to junction circuit 900 which is unique to it.



  The junction circuit 900 is connected via a junction 1030 to the arrival selector 1036 which is individual to it.



  In addition, the junction circuit 900 includes an inbound junction 1040 accessible to the selectors of the searcher-selector junctions associated with the different long-distance operator positions of the Strowger 1060 automatic trunk switchboard.



   DEVICES INCORPORATED IN THE SYSTEM
AUTOMATIC TELEPHONY
Preferably, the powerline system connecting the remote exchange 10 to the main office 40 and the powerline system connecting the main office 40 to the remote office 50 are identical and each of them has a Lenkurt type 32 element.



  According to one variant, the power line equipment connecting the various exchanges, offices and repeater indicated can be of a radio link type. In this way, the powerline carriers 494,794 and 994, arranged at the east end of the respective lines 60, 70 and 80 and carrying respectively parts of the first channels of the three indicated carrier systems, transmitting a carrier frequency of 15.95 kilocycles for signaling, and the lower sideband of the carrier frequency of 15.95 kilocycles (13.1 to 15.7 kilocycles) for communications, and receives a carrier frequency of 24.65 kilocycles for signaling and the lower sideband of the carrier frequency 24.55 kilocycles (21.7 to 24,

  3 kilocycles) for communications. Similarly, carrier current devices 394, 694 and 894 arranged at the western end of lines 60, 70 and 80 and respectively comprising parts of the first channels of the three carrier current systems indicated, transmitting a carrier frequency of

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 24.65 kilocycles for signaling the lower sideband of the carrier frequency of 24.55 kilocycles - (21.7 to 24.3 kilocycles for communications, and receive a carrier frequency of 15.95 kilocycles for signaling and the lower sideband of the carrier frequency of 15.95 kilocycles (13.1 to 15.7 kilocycles) for communications.



   In addition, each carrier current device 394, etc ... has a signal output transmission path comprising a first carrier frequency oscillator and a transmitter amplifier whose anode circuit is controlled by a signal output relay. associated and an outgoing communications path comprising a balanced modulator connected to the first carrier frequency oscillator and an associated transmit bandpass filter.



  In addition, each powerline carrier equipment shown has a signal input channel comprising a rectifier and a signal input relay as well as a communications input channel comprising a balanced demodulator connected to a second. carrier frequency oscillator and an associated receive bandpass filter. On the other hand, each powerline carrier equipment indicated has a transmit direction filter connected to the associated signal output transmission path and the associated communications output path as well as a receive direction filter connected to the associated signal input channel and the associated communications input channel.

   In addition, each powerline carrier equipment shown has a line high pass filter mounted between the associated line end, the transmit direction filter, and the receive direction filter. Finally, each end of the line is connected by a low-pass filter to other vocal frequency devices.



  The conventional apparatuses described above allow the use of lines 60, 70 and 80 with other voice frequency apparatus in a manner which will be readily understood by the technician.

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   As shown in figure 2, all the seeker-selector junctions 203, etc ..., all the urban connectors ns 205, etc ... and all the arrival selectors 206, etc ... are, preferably, of the conventional Strowger type, while distributor 204 and line circuits 213, 214, etc. are of any suitable type. Finally, each of the T II subscriber sets, etc ... is provided with a conventional handset, each subscriber line 2II, etc ... is provided with an individual counter (not shown) and all the sets to prepayment T 12, etc ... are of a type already known.

   More precisely, a prepayment station of this type comprises, among other elements, an emitter shunted by an asymmetrical current conducting device in the form of a copper oxide rectifier, so that an individual can, at the prepaid set, order the establishment of a call and enter into conversation with an attendant without inserting a coin or token into the device.

   In addition, the individual can normally establish a communication between the prepaid set and a subscriber set, but he cannot speak to the called subscriber until he has inserted a coin into the prepaid device. currency or a token, as a result of the blocare effect of the copper oxide receiver against the transmitter when the line polarity is reversed in an urban communication.



   In addition, each of the junction circuits of the remote exchange 10 is identical to the junction circuit 200 which comprises, as shown in Figures 2 and 3, a group of relays comprising a time relay R 235, a reversing relay. battery R 240, one series relay R 250, one switching relay R 260 one monitoring relay R 270, one time relay R 280, one response relay R 310, one dial relay R 320, one relay R 330, one R 340 sticking relay, one R 350 signal input relay, two R 360 and R 370 digit relays, one R 380 sticking relay, and one R 390 tone relay.

   In addition, the

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 Junction circuit 200 comprises an impedance 257 and a busy signal transformer 346. It will be noted here that the junction circuit 200 is connected to the carrier current equipment 394 by a pair of line conductors C 301 and C 302 a C signal output conductor 303 and a C 304 signal input conductor and that the devices provided in powerline carrier apparatus 394, as previously discussed, include a signal input relay R 395 and an R 397 signal output relay.



   At the tandem exchange 20, as shown in FIG. 4, all the seeker-selector junctions 426, etc ..., all the urban connectors 427, etc ... and all the arrival selectors 429, etc ... and 434, etc ... are conventional Strowger type, while distributor 425 and line circuits 423, 424, etc ... are of any suitable type. Finally, each of the subscriber sets T 21, etc ... is provided with a conventional handset, each of the subscriber lines 421, etc ... is provided with an individual meter (not shown) and the prepaid sets T 22, etc., are of a type already known.



   At the tandem exchange 20, each of the junction circuits of the group comprising in particular the junction circuit 400 is preferably identical to said circuit which comprises, as shown in FIG. 4, a group of relays comprising a monitoring relay R 440, one response relay R 445, one signal input relay R 450, one numbering relay R 455, one switching relay R 460, one line relay R 470, one sticking relay R 480, one control R 490, an R 400 bonding relay and an impedance 458. It will be observed here that the junction circuit 400 is connected to the carrier current device 494 by a pair of line conductors C 401 and C 402, a conductor C 403 signal output conductor and a C 404 signal input conductor and the devices provided in powerline carrier switchgear 404,

   as explained previously, comprising a signal input relay R 495 and a signal output relay

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 Signals R 497.



   In addition, at the tandem exchange 20, each of the junction circuits of the group comprising in particular the junction circuit 500 is preferably identical to said junction circuit, which comprises, as shown in Figures 5 and 6, a group of relays comprising one R 530 battery changeover relay, two R 540 and R 550 time relays, one R 560 monitoring relay, one R 565 tone relay, one R 570 lift relay, one R 580 monitoring relay , an R 585 attack relay, an R 590 control relay, an R 595 response relay, an R 610 line relay, an R 620 pulse relay, an R 630 switching relay, and a number relay - tion R 640. In addition, the junction circuit 500 has an indicated ordinary battery, a surge battery 616 and an RC 650 repeater coil.



   Preferably, each of the junction circuits of the repeater 30 is identical to the junction circuit 600 which comprises, as shown in FIG. 6, a group of relays comprising: a signal output relay R 660 and a signal input relay R 670. In addition, the junction circuit 600 comprises two asymmetrical current conductors 666 and 667 in the form of copper oxide rectifiers and a repeater coil RO 675.

   It will be observed here that the junction circuit 600 is connected to the power line carrier 694 by a pair of line conductors c 601 and C 602, a signal output conductor C 603 and a signal input conductor C 604 and that the devices provided in powerline carrier switchgear 694, as explained above, include an R 695 signal input relay and an R.697 signal output relay.



   Preferably, at repeater 30, each of the warning pulse transmitters is identical to the warning pulse transmitter 680 which, as shown in FIG.

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 6, a motor 681 which can be controlled from a commercial single phase AC power source and which is associated with a set of S 682 switching springs and a gear box 683. The gear box 683 is capable of regulating the operation of the motor 681 over time and, after a period of ten minutes, it opens the associated contacts S 684 and closes the associated contacts S 685.

   In addition, the warning pulse transmitter 680 has an R 686 start relay.



   At the main office 40, each of the junction circuits of the group comprising, in particular, the circuit ee junction 700 is preferably identical to it. Said junction circuit 700, as shown in FIG. 7, ends on the jack J 730 in front of it. switchboard 765, as previously indicated, and comprises a relay group comprising an R 705 signal input relay, a jaok relay, R 710 and an R 720 plug relay. Junction circuit 700 comprises an L 732 busy lamp and an L 733 line lamp arranged at the attendant switch board 765.

   It will be observed here that the junction circuit 700 is connected to the power line carrier 794 by a pair of line conductors C 701 and C 702, a signal output conductor C 703 and a signal input conductor. C 704 and that the devices provided in powerline carrier equipment 794, as explained previously, include an R 795 signal input relay and an R 797 signal output relay.



   Preferably, each of the dicords of the attendant switch board 765 is identical to the dicord 766 which, as shown in Figure 7, terminates at the front plug P 748 and the rear plug P 758 respectively and has a dial of call D 760, a dial key K 737, a call key K 736, a front talk key K 734 and a rear talk key K 735. In addition, the dicorde 766 has a front monitoring lanpe L 747, one L 757 rear monitoring light

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 and a relay group comprising a front dial relay R 740, a front monitor relay R 745, a rear dial relay R 750 and a rear monitor relay R 735.

   Finally, it should be noted that the dichord 766 is associated with a headset 767 disposed at the operator switch panel 765 and with an intermittent operation generator 738.



   Preferably, at main office 40, each of the warning signal receivers is identical to the warning signal receiver 770, which includes, as shown in FIG. 7, a motor 773 operable by a commercial source. - single-phase AC energy cial and which is associated for its operation with two sets of switch contacts S 777 and S 778 and with a gearbox 774. The gearbox 774 is capable of adjusting over time the engine operation and to close, after nine and a half minutes the associated S 775 contacts and, after ten and a half minutes, the associated S 776 contacts.

   On the other hand, the warning signal receiver 770 has a relay group comprising a warning relay R 780, a starting relay R 785, a sticking relay R 790 and a time relay R 700. Finally, the junction circuit 700 comprises a warning lamp L 771, a delayed warning device DA 772 and a correction key K 773.



   At the main office 40, each of the junction circuits of the group comprising in particular the junction circuit 800, is preferably identical to said circuit which terminates on the J jack 815 in front of the operator switch board 765, as indicated above, and comprises a relay group consisting of an R 820 plug relay, an R 830 signal output relay, an R 835 jack relay, an R 850 glue relay, an R 855 dial relay, an R signal input relay 860, two second call relays R 865 and R 870, one communication relay

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 R 880 station and an R 890 response relay. In addition, the junction circuit 800 has an RC 875 repeater coil and an L 817 battery lamp arranged at the operator's switchboard 765.

   It will be seen here that the junction circuit 800 is connected to the powerline carrier 894 by a pair of line conductors C 801 and C 802, a signal output conductor C 803 and a signal input conductor C 804 and that the devices provided in powerline carrier switchgear 894, as explained previously, include an R 895 signal input relay and an R 897 signal output relay,
At main office 40, as shown in Fig. 8, city switch train 844, trunk switch train 805 and inbound selectors 812, etc. are preferably of the conventional Strowger type, while the distributor 843, line circuits 842, etc ... direct traffic junctions 846, etc ...

   and inbound trunk trunks 809, etc., are of any suitable type. Finally, each of the T 41 subscriber sets, etc. is provided with a conventional handset.



   At the remote office 50, each of the trunk circuits is preferably identical to the trunk circuit 900 which comprises, as shown in Figures 9 and 10, a group of relays comprising an R signal input relay 920, a relay sticking R 930, one dialing relay R 940, one fault relay R 950, one attack relay R 955, one switching relay R 960, one second call relay R 970, one end of dialing relay R 980, one response relay R 975, one line relay R 1010, one fault relay R1020 and one second call relay R 1025, In addition, the junction circuit 900 has an RC 910 repeater coil.

   It will be observed here that the junction circuit 900 is connected to the powerline carrier apparatus 994, by a pair of line conductors C 901 and C 902, a signal output conductor C 903, and a

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 signal input conductor C 904 and that the devices provided in powerline carrier switchgear 994, as explained previously, include an R 995 signal input relay and an R 997 signal output relay.



   At remote office 50, as shown in Fig. 10 city switch train 1054, trunk switch train 1038, inbound selectors 1036, etc ... and seeker-selector junctions 1062, etc,., Are, preferably of the classic Strowger type, while distributor 1053, line circuits 1052, etc ..., direct traffic junctions 1056, etc ..., and incoming trunk junctions 1066, etc ... are of any suitable type. On the other hand, the Strowger 1060 automatic trunk switchboard is of an already known type. Finally, each of the T 51 etc. subscriber sets is fitted with a conventional handset.



   The connection and arrangement of the apparatuses of the automatic telephone system shown in FIG. 1 and described briefly above, will be better understood from the examples indicated below of establishment of communication between the various exchanges and offices.



     URBAN CALLS TO REMOTE CENTRAL 10
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It will be assumed first of all that a call initiated by a subscriber station such as, for example, the subscriber station T 11 of the center
 EMI21.2
 The remote exchange 10 must be routed to a pay station such as, for example, the prepayment station T 12 of said remote exchange 10. When the call is initiated at the calling subscriber station T 11, the call circuit. line 213 associated with the subscriber line 211 operates in such a way as to indicate the subscriber line 211 as being occupied at the urban connectors 205, etc ... which have access to said line and so as to trigger the operation of the distributor 204.

   The distributor 204 designates a free finder-selector junction such as, for example, the junction

  <Desc / Clms Page number 22>

 first group selector finder 203, to be used at this time, so that the selector finder 203 junction finder operates and attacks subscriber line 211.



  The subscriber of the calling subscriber set T II then forms on his dial the call number of the prepaid set T 12, a call number which can be 112 for example. The selector of the searcher-selector junction 203 responds to the first digit "1" and selects the first group of urban connectors comprising the urban connector 205 then a free urban connector in said group.

   For example, the selector finder junction selector 203 may select the junction 207 terminating at the particular city connector 205, after which the city connector 205 is made responsive to the next two digits formed on the call dial or telephone extension. calling subscriber T II.



  The subscriber of the calling subscriber station T II then proceeds to the formation on his dial, of the following two digits "I" and "2" which makes the urban connector 205 operate, in such a way that it attacks the line 212 leading to the requested prepayment station T 12; at this moment, the occupation or free state condition of line 212 is checked by a test carried out by urban connector 205.



   It will first of all be assumed that the requested prepayment powte T 12 is occupied at this time. The urban connector 205 tests the line 212 which ends at said station, finds that it is busy and returns a busy tone current to junction 207, the searcher-selector junction 203 and the subscriber line 211, to the calling subscriber set T II, so as to indicate to the subscriber of said set that the desired call cannot be obtained at this time because of the occupation condition of the requested prepaid set T 12. The subscriber of the calling subscriber station T II then hangs up his apparatus in a manner which will be described later in a more detailed form.

  <Desc / Clms Page number 23>

 



   On the other hand, it will be assumed that the requested prepaid set T 12 is free at the time of the call. Under these conditions, the urban connector 205 operates in such a way as to apply an inrush current on line 212 to the requested prepayment station T 12 and to send back a total warning current to the calling party of the called party's call. on the junction 207 and, consequently, towards the calling subscriber station T 11, so as to indicate to the subscriber of said station that the requested prepayment station T 12 is called.

   When someone answers the call at the requested prepayment station T 12, the urban connector 205 operates so as to reverse the polarity of the junction 207, so that the searcher-selector junction 203 acts on the meter (not shown) associated with the subscriber line 211, so as to proceed with the counting of the call in a conventional manner. At this moment, the communication is completely established between the calling subscriber station T 11 and the requested prepaid station T 12 and the conversation between these two stations is carried out in the usual way.



     At the end of the established communication, when the person speaking to the requested prepayment station T 12 hangs up, the urban connector 205 operates in such a way as to reverse the polarity of the junction 207 again, but this time without effect.



  Then, when the subscriber of the calling subscriber station T 11 hangs up, the loop circuit leading to the city connector 205 is interrupted, so that the city connector 205 and the searcher-selector junction 203 are released.



  When the urban connector 205 is released in this way, the line 212 which ends at the requested prepayment station T 12 is again indicated as free by the line circuit associated 214 with the city connectors 205, etc ... which have access to said station . Likewise, when the searcher-selector junction 203 is released in this way, the subscriber line 211 which terminates at the calling subscriber station T II is indicated as free by the line circuit 213 at the city connectors 205,

  <Desc / Clms Page number 24>

   ete ... who have access to said post.

   In addition, when the seeker-selector junction 203 is released in this manner, the junction 207 which terminates at the city connector 205 is indicated as free at the seeker-selector junctions 203, etc ... which have access to said junction 207. At this moment, the communication established between the calling subscriber station T II and the requested prepayment station T 12 is interrupted and all the devices involved in said communication are completely released and become available for later use.



   From the foregoing it will be understood that a communication can be established between a calling subscriber station T 11, etc. of the remote exchange 10 and another called subscriber door of said exchange in an identical manner. . From me it will be understood that a call from a prepaid calling station T 12 etc ... of the remote exchange 10 can be routed to a called subscriber station T II, etc ... 'or to another prepaid station requested from said exchange in a substantially identical manner.



  It will be noted with regard to the routing of a communication between the requesting prepaid station: 12 of the remote exchange 10 and a requested subscriber station or another requested prepaid station of said central, that when the call is followed by a response, the urban connector 205 operates in such a way as to reverse the polarity of the junction 207 and through the selector searcher junction used and the line 212 the polarity applied to the requesting prepayment station T 12. This polarity reversal at the prepayment station applicant T 12 causes the transmitter of said station to be blocked by the associated copper oxide rectifier, unless the person wishing to use the prepayment station T 12 has introduced the token into this device at this time. necessary.

   More precisely, in the case where the person wishing to use the prepaid set T 12 has not deposited a token at this time, he can hear the person answering the requested subscriber set or the prepaid set requested from the remote exchange. 10, but she cannot enter into conversation with

  <Desc / Clms Page number 25>

 said person due to the fact that the copper oxide rectifier blocks the associated transmitter as a result of the polarity reversal at the requesting prepayment station T 12. On the other hand when the person who wishes to use the requesting prepayment station T 12 introduces a token in this apparatus, the rectifier with the copper oxide no longer blocks the transmitter of said station, so that the communication is established in the manner explained previously.



   CALL FROM A SUBSCRIBER STATION OR FROM A STATION
PREPAYMENT OF THE REMOTE CENTRAL 10 AND INTENDED FOR A
SUBSCRIBER POST OR A PREPAYMENT POST OF THE CENTRA
IN TANDEM 20
It will first be assumed that a call made to a subscriber station such as, for example, the subscriber station T II of the remote exchange 10 is to be routed to a subscriber station such as, for example, the subscriber station T 21 of the tandem exchange 20.



  When the call is initiated at the calling subscriber station T II, the line circuit 213 associated with the subscriber line 2II operates so as to indicate to the urban connectors 205, etc ... 'which have access to the line of 'subscriber 211 that said line is busy and so as to trigger the operation of the distributor 204, the distributor 204 designates one of the free selector searcher junctions such as, for example, the selector searcher junction 203 of the first group with a view to its use at this time, so that the searcher-selector junction 203 attacks the subscriber line 211.



   The subscriber of the calling subscriber station T II of the remote exchange 10 then forms on its dial a code number such that, for example, the code number "9" indicating the call must be routed to the exchange in tandem 20, said figure being followed by the call number of the called subscriber station T 21 of the tandem exchange 20, which may for example be "I2I", Thus, the subscriber of the calling subscriber station T II form first on its

  <Desc / Clms Page number 26>

 dial the indicative number "9", so that the selector of the researcher-selector junction 203 responds to the first digit "9" to select the bundle of junctions comprising in particular the junction 225 then a free junction in said bundle, By example,

   the selector of the seeker-selector junction 203 can select the particular junction 225 assuming that the junction circuit 200 is free at this time, the junction 225 being indicated as free to the selector of the finder-selector junction 203 by the application from a battery potential to its control conductor C 223. More precisely, a battery potential is normally applied through the intermediary of the impedance 257 and the contacts 266 and 383 to the control conductor C 223 of the junction 225.



   In addition, when the selector of the seeker-selector junction 203 drives junction 225, a loop circuit is closed for energizing the upper and lower windings of line relay R 330 in junction circuit 200. - Said loop circuit is established as follows earth, contacts 362, lower winding of line relay R 330 contacts 244, line conductor C 227 of junction 225 and battery, upper winding of line relay R 330, contacts 342, conductor of line C 226 of junction 225.



  When this loop circuit is thus closed, the line relay R 330 operates and closes, at contacts 331, an obvious circuit for the energization of the sticking relay R 380. When operating, the sticking relay R 380 interrupts, at contacts 383, a point of the circuit previously traced by the application of a battery potential to the control conductor C 223 of junction 225 and closes to contacts 384, a circuit passing through the upper winding of tone relay R 390 for the application of an earth potential to the control conductor C 223 of the junction 225.

   When the battery potential is thus eliminated from the control conductor C 223 and replaced on this conductor by an earth potential, the junction 225 and,

  <Desc / Clms Page number 27>

 therefore, junction circuit 200 are indicated as busy selector of other seeker-selector junctions which have access to said circuit and to said junction.

   In addition, the upper winding of the totality relay R 390 is energized so that said relay operates and closes, at contacts 391, an obvious circuit for the application of an earth potential to the trigger conductor of the operation of the generator. C 349 tone, which ensures said triggering In addition, the bonding relay R 380 interrupts, at contacts 381, a normally closed termination circuit further comprising contacts 311, resistor 344, contacts 281, capacitor 286 and capacitors 347 and 348 mounted between line conductors C 301 and C 302 leading to carrier current equipment 394.

   In addition, in operation, line relay R 330, closes, at contacts 333, an obvious circuit for the application of an earth potential to the signal output conductor C 303 leading to powerline carrier switchgear 394 , so as to cause the excitation of the signal output relay R 397 in said switchgear, When operating, the signal output relay R 397 of the carrier current device 394 closes the contacts 398 included in the circuit. the anode of the associated transmission amplifier, so that the 24.55 kilocycles carrier signal from the associated carrier frequency oscillator is transmitted for signaling purposes on the associated line 60 which connects the remote exchange 10 to the exchange in tandem 20.



   When the carrier signal at 24.55 kilocycles is received in the carrier current apparatus 494 of the tandem exchange 20 the carrier current apparatus 494 causes the armature of the normally actuated signal input relay R 495 to release. . This last relay, by releasing its armature, closes the contacts: 496 applying an earth potential to the signal input conductor C 404 so as to cause the excitation of the signal input relay R 450 in the junction circuit

  <Desc / Clms Page number 28>

 400.

   In operation, the signal input relay R 450 forms, at contacts 452, an obvious circuit for energizing the bonding relay R 400, which closes, when operating, at contacts 405, a circuit comprising contacts 485 for the 'energization of the upper winding of the switching relay R 460, so that the latter is energized. While operating, the switching over again R 460 interrupts, at contacts 466, a normally closed circuit comprising impedance 458 and contacts 483 for the application of a battery potential to the control conductor C 433 of junction 430 and closes, at contacts 467, a circuit passing through contacts 483 for the application of an earth potential to the control conductor C 433.

   When the battery potential which was applied to the control conductor C 433, is thus replaced by a ground potential, the junction 430 is indicated as occupied to the arrival selectors 434, etc., and to the selectors of the searcher junctions. selector 426, etc ... which have access to said junction, so that the junction circuit 400 is indicated as busy at the above switches.



   In addition, when operating, switching relay R 460 closes, at contacts 463, a circuit passing through contacts 451 and bypassing the right winding of response relay R 445 on line conductors C 436 and C 437 of the junction 435 which ends in the arrival selector 429, so that the arrival selector 429 operates and returns a ground potential on the control conductor C 438 of the junction 435, so as to energize in multiples the winding of left of response relay R 445 and the lower winding of switching relay IL 460.

   Consequently, a bonding circuit is thus closed for the energization of the lower winding of the switching relay R 460, and the current flowing through the left winding of the response relay R 445 is not in the direction wanted so that said relay is energized,

  <Desc / Clms Page number 29>

 
At this time, the arrival selector 429 is conditioned in such a way that it is sensitive to the first digit which is transmitted to it by the junction 435.

     the subscriber of the calling subscriber station T II of the remote exchange
10 then forms on its dial the first digit "l" of the call number of the called subscriber station T 21 of the tandem exchange 20, so that the line relay R 330 on the junction circuit 200 follows the uhic impulse of the first number "1" by releasing its frame, then pulling it again. During these two operations, the line relay R 330 interrupts and then closes, at contacts 331, the previously indicated circuit which kept the sticking relay R 380 energized, but this last relay which, is of the delayed release type, remains actuated for the passage of impulse.



   In addition, by releasing and then drawing its armor again, the line relay R 330 closes and then interrupts at contacts 332 a circuit comprising the contacts 387 for energizing the numbering relay R 320, in such a manner. so that it attracts its armature and remains actuated during the passage of the pulse, given that it is of the delayed release type. While operating, the rotation number relay R 320 closes, at contacts 324, another terminating circuit passing through contacts 311, resistor 344, contacts 281, conductor 286 and capacitor 347 and 348 in branch on the line conductors. C 301 and 0 302 leading to the post current apparatus 394.

   On the other hand, by releasing and then attracting its armature again, the line relay R 330 interrupts then reforms, at contacts 333, the circuit previously indicated for the application of an earth potential to the signal output conductor C 303, so that the signal output relay
R 397 releases his frame and then draws it again. During these two operations, it interrupts then closes again, at the contacts

  <Desc / Clms Page number 30>

 398, the anode circuit of the associated transmission amplifier, so that the carrier signal at 24.55 kilocycles is removed and then applied again to line 60 connecting the remote exchange 10 to the tandem exchange 20.



   When the carrier signal at 24.55 kilocycles is removed and then reapplied to line 60, the signal input relay R 495 of the carrier current device 494 of the tandem central 20 attracts and then releases its armature. by interrupting and then closing, at contacts 496, the circuit previously indicated for the application of an earth potential to the signal input conductor C 404, which causes de-energization and then re-energization of the relay. input of R 450 signals into junction circuit 400.

   By releasing its armature, then pulling it in again, the R 450 signal input relay interrupts then closes, at contacts 452, the previously indicated circuit which kept the R 400 bonding relay energized, so that the latter relay , which is of the delayed release type, remains actuated during the passage of the pulse. In addition, by releasing its armature and then pulling it again, the signal input relay R 450 closes and then interrupts, at contacts 453, a circuit passing through contacts 406 for energizing the numbering relay R 455; so that the latter relay attracts its armature and remains actuated during the passage of the pulse, given that it is of the delayed release type.

   By attracting its armor, the dial relay R 455 closes an obvious circuit at contacts 457 through resistor 454 and bypassing the left winding of the response relay R 445.



  Finally, by releasing its armature, then pulling it in again, the signal input relay R 450 interrupts then closes, at contacts 451, the previously traced loop circuit passing through the line conductors C 436 and C 437 of the 435 junction which leads to the arrival selector 429, so that the single pulse of the first digit "1" of the call number

  <Desc / Clms Page number 31>

 from the called subscriber station T 21 is retransmitted on the junction 435 to the arrival selector 429.

   The arrival selector 429, when it receives the number "1" selects the bundle of junctions leading to the first group of urban connectors comprising the urban connector 427, then selects a junction in said faaceau, For example, the arrival selector 429 may select the junction 428 terminating at the particular city connector 427, so that the particular city connector 427 is conditioned to be sensitive to the next two digits transmitted on the junction 435.



   At the end of the training, the first digit "1" dialed to the calling subscriber set! .. 1! from the remote exchange 10. the line relay R 330 of the junction circuit 200 is maintained in its energized position, as indicated above and a short time later the numbering relay R 320 releases its armature, since 'it's the delayed release type.



   By releasing its armature, the numbering relay R 320 interrupts, at contacts 324, the other terminating circuit indicated above and bypassing the line conductors C 301 and C 302 leading to the powerline carrier switchgear 394. D ' on the other hand, at the end of the formation on the call dial of the first digit "1" at the calling subscriber station T II, the signal input relay R 450 of the junction circuit 400 is maintained in its position. excitation position and a short time later, the numbering relay R 455 releases its armature to interrupt, at contacts 457, the previously drawn circuit comprising resistor 454 and short-circuiting the right winding of the response relay 445,

     so that the right winding of the dial relay R 455 is energized again in the previously drawn loop circuit including junction 435 and terminating at arrival selector 429. However, the relay

  <Desc / Clms Page number 32>

 response R 445 is not at this moment traversed by a current of a direction of polarity capable of ensuring its excitation.



   At this moment, the subscriber of the calling subscriber station T 11 of the remote exchange 10 has formed on his dial the first digit "1" of the call number of the called subscriber station T 21 of the tandem exchange 20, from so that the line relay R330 of the junction circuit 200 has operated according to the indicated figure by retransmitting it to the carrier current device 394. The signal output relay R 397 of the carrier current device 394 retransmits the indicated digit on line 60 to power line carrier 494. signal input relay R 495 of power line carrier 494 retransmits the indicated digit to signal input relay R 450 of junction circuit 400 .

   The signal input relay R 450 retransmits the figure indicated on the junction 435 to the arrival selector 429 and the arrival selector 429 operates according to said number, so as to select the free urban connector 427 of the corresponding group. Similarly, the subscriber of the calling station T II of the remote exchange 10 forms on his dial the second and third digits "2 and" 1 "of the call number of the called subscriber station T 21 of the tandem exchange. These two digits are retransmitted in the manner previously discussed at city connector 427.

   The urban connector 427 operates upon receipt of the second digit "2" of the call number of the called subscriber station T 21 of the tandem exchange 20 and selects the corresponding group of subscriber lines, then responds to the third digit "1 "of the call number of the called subscriber station T 21 by selecting the subscriber line 421 which ends at said station, at this time, the urban connector 427 operates and tests the requested subscriber station T 21 following - before the usual practice.



   In the event that the subscriber station requests T 21 is busy at this moment, the line circuit 423 which is individual to the subscriber line 421, terminating at said station, indicates the condition observed to the urban connector 427. urban connector

  <Desc / Clms Page number 33>

 427 then ensures the return of a busy tone current to junction 428 and arrival selector 429 and to line conductors C 436 and C 437 of junction 435.

   At this moment, the line conductor C 436 of the junction 435 is connected through the intermediary of the contacts 463, 456 and 462 to the line conductor C 402 which ends in the power line equipment 494 and the line conductor C 437 of junction 435 is connected through contacts 451 and 465 to the C line conductor 401 which terminates at powerline carrier apparatus 494, Accordingly, a busy tone current is returned through the previously traced circuit comprising line conductors C 401 and C 402 to powerline carrier equipment 494.

   The balanced modulator of said switchgear then operates by transmitting the lower sideband of the 15.95 kilocycles carrier signal modulated by the acoustic frequency busy signal on line 60 connecting the tandem exchange 20 to the remote office 10. When the sideband lower of the carrier signal at 15.95 kilocycles modulated by the occupancy signal at acoustic frequency is received by the carrier current equipment 394 of the centrà. remote 10, the balanced demodulator of said apparatus demodulates the received signal by transmitting its modulator component closed by the busy signal at acoustic frequency on the line conductors C 301 and C 302 which are coupled by the circuit previously traced to the conductors of line C 226 and C 227 of junction 225.

   The acoustic frequency busy signal sent back over line conductors C 226 and C 227 of junction 225 is sent back through selector finder junction 203 and subscriber line '10 211 to the subscriber station. calling party T II of the remote exchange, which indicates to the subscriber of said station that the desired call cannot be obtained at this time due to the condition of receiving the called subscriber station T 21 of the tandem exchange 20.



  The subscriber of the calling subscriber station T II of the remote exchange 10 then proceeds to hang up his apparatus in the manner which

  <Desc / Clms Page number 34>

 will be discussed in more detail below.



   If, on the other hand, the requested subscriber station T 21 of the tandem exchange 20 is free when the urban connector 427 selects by operating the subscriber line 421 which ends at said station, the urban connector 427 applies a call corrant to the subscriber line 421 which terminates at the requested subscriber station T 21 and triggers the operation of the line circuit 423 associated with the subscriber line 421 so as to indicate that said line 421 is busy at the other urban connectors of the associated group .



  In addition, the city connector 427 returns a called party caller's warning tone current over junction 428, inbound selector 429, and line conductors C 436 and C 437 of junction 435. Calling party warning tone current of called party calls the powerline carrier 494 of the central office in tandem 20 and the powerline carrier 394 of the remote exchange 10 to operate in the manner previously discussed, so that called party call warning tone current is returned to trunk circuit 200, trunk 225,

   the selector searcher junction 203 and the subscriber line 211 to the calling subscriber station T II of the remote exchange 10 so as to indicate to the subscriber of said station that the subscriber of the called station T 21 of the tandem exchange 20 is called.



   When the subscriber of the called station T 21 of the tandem exchange 20 answers the call, the urban connector 427 operates and reverses the polarity of the junction 428 and, consequently, that of the line conductors C 436 and C 437 of the junction 435 on arrival selector 429, so that the right-hand winding of response relay R 445 of junction circuit 400 is then carried by a current of polarity such that said relay is energized.



  By attracting its armature, the response relay R 445 interrupts, at contacts 446, a normally closed termination circuit comprising the capacitor 443, the resistor 444, and the contacts 471 in shunt on line conductors C 401 and C 402

  <Desc / Clms Page number 35>

 terminating at carrier switchgear 494 and closes, at contacts 447, an obvious circuit for energizing the upper winding of the R 440 monitoring relay so that the latter relay attracts its armature. While operating, the R 440 monitoring relay closes at contacts 442 an obvious circuit for the application of an earth potential to the signal output conductor C 403, so as to cause the signal output relay to be energized. R 497 of carrier current switchgear 494.

   When operating, the signal output relay R 497 of power line carrier 494 closes the contacts 498 included in the anode circuit of the associated transmission amplifier, so that the carrier frequency oscillator associated transmits the carrier signal at 15.95 kilocycles on line 60 which connects the tandem exchange 20 to the remote exchange 10.



   When the carrier signal at 15.95 kilocycles is received by the carrier current apparatus 394 of the remote exchange 10, the apparatuses of said exchange cause the armature of the signal input relay R 395 to release. By releasing its armature , the signal input relay R 595 of the powerline carrier switchgear 394 closes at the contacts 396 a circuit for the application of an earth potential to the signal input conductor C 304, so to cause the energization of the signal input relay R 350 of the junction circuit 200. By drawing its armature, the signal input relay R 350 closes, at contacts 352, an obvious circuit for the energization of the relay gluing R 340.

   By attracting its armature, the bonding relay R 340 closes, at contacts 341, a circuit comprising the contacts 385 and 256 which ensures the energization of the time relay R 235 a short instant later, given that the latter relay is of the type delayed attraction. While operating, the time relay R 235 closes, at contacts 237, a circuit passing through the contacts

  <Desc / Clms Page number 36>

 352 for energizing the reverse relay, battery ion R 240.



  By operating the reverse R 240 battery reversing relay, at contacts 241, 242, 243 and 244, the polarity of line conductors C 226 and C 227 of junction 225 with respect to the upper and lower windings of the line relay R 330 of the junction circuit 200. When the polarity of the junction 225 is thus reversed, the counter (not shown) associated with the subscriber line 211 of the calling subscriber is activated and ensures the counting of the conversation between the calling subscriber station T 11 of the remote exchange 10 and the called subscriber station T 21 of the tandem exchange 20.



   At this time, a communication is established between the calling subscriber station T II of the remote exchange 10 and the called subscriber station T 21 of the tandem exchange 20. When an acoustic frequency signal is transmitted to the subscriber station requesting T II, it is transmitted on the previously traced circuit comprising the line conductors C 301 and C 302 to the power line equipment 394 of the remote exchange 10. The power line equipment 394 then operates by transmitting the band lower side of the carrier signal at 24.55 kilocycles (21.7 to 24.3 kilocycles) on line 60.

   When the carrier current equipment 494 of the tandem exchange 20 receives the lower sideband of the carrier signal at 24.55 kilocycles (21.7 to 24.3 kilocycles), it operates and transmits the acoustic component of said bridle on the circuit previously traced comprising the line conductors C 401 and C 402 at the requested subscriber station T 21. In a similar manner, when a signal at acoustic frequency is sent to the requested subscriber station T 21, it is transmitted on the previously drawn circuit comprising line conductors C 401 and C 402 to powerline switchgear 494 of tandem exchange 20, so that powerline switchgear 494 operates by passing the lower sideband of the carrier signal to 15.95 kilocycles (13.1 to 15.7 kilocycles) on line 60.



  When the apparatus 493 of the remote exchange 10 receives said

  <Desc / Clms Page number 37>

 band it operates and transmits the acoustic component of this band on the previously traced circuit comprising the line conductors C 301 and C 302 to the requesting subscriber station T II.



   At the end of the communication established, when the subscriber of the called station T 21 of the tandem exchange 20 hangs up, the urban connector 427 again inverts the polarity of the junction 428 and of the arrival selector 429 with respect to the line conductors C 436 and C 437 of the junction 435, so that the right winding of the response relay R 445 of the junction circuit 400 receives a current of a polarity such that it releases its armature.



  By releasing its armature, the response relay R 445 closes, at contacts 446, the termination circuit previously traced in bypass on the line conductors C 401 and C 402 leading to the power line switchgear 494 and interrupts, at the contacts 447, the circuit previously indicated for the excitation of the upper winding of the monitoring relay R 440, in such a way that the latter relay releases its armature a short instant later, given that it is of the type rela- deferred payment.

   By releasing its armature, the monitoring relay R 440 interrupts, at contacts 442, the circuit previously drawn for the application of an earth potential to the signal output conductor C 403, which causes the release of the armature of the signal output relay R 497 of the power line carrier 494. By releasing its armature, the signal output relay R 497 interrupts, at contacts 498, the anode circuit of the transmission amplifier associated, so that the carrier signal at 15.95 kilocycles is removed from line 60.



  When the carrier signal at 15.95 kilocycles is thus removed from line 60, the carrier current device 394 responds by re-energizing the signal input relay R 395 of said device. By attracting its armature again, the signal input relay R 395 of powerline carrier switchgear 394 interrupts, at contacts 396, the circuit previously indicated for the application of an earth potential to the conductor.

  <Desc / Clms Page number 38>

 C 304 signal input relay, which de-energizes the R 350 signal input relay of junction circuit 200. By releasing its armature, the R 350 signal input relay interrupts the circuits at contacts 352. multiple previously drawn which kept the R 340 bonding relay and the R 240 battery reversing relay actuated.

   Since the R 340 bonding relay is of the delayed release type, its armature releases a short time later and the R 240 battery reversing relay releases its own immediately. By releasing its armature, the battery inversion relay R 240 inverts again, at contacts 241, 242, 243 and 244 the polarity of junction 225 with respect to the upper and lower windings of the line relay R 330, but without no effect. at this time. By releasing its armature, the bonding relay R 340 interrupts, at contacts 341, the circuit previously drawn which kept the time relay R 235 energized.



   When the subscriber of the calling subscriber station T II of the remote exchange 10 then hangs up his apparatus, the previously drawn loop circuit which kept the line relay R 330 of the junction circuit 200 energized is interrupted. By releasing its armature, the line relay R 330 interrupts, at contacts 331, the circuit previously drawn which kept the bonding relay R 380 energized, so that the latter relay releases its armature a short time later, given that it is of the delayed release type. Moreover, by releasing its armature, the line relay R 330 interrupts, at contacts 333, the circuit previously indicated for the application of an earth potential to the signal output conductor C 303, which causes the relay to de-energize. R 397 signal output of powerline carrier equipment 394.

   By releasing its armature, the R 380 bonding relay closes, at contacts 381, the previously traced termination circuit comprising resistor 344 and capacitor 286, as well as capacitors 347 and 348 in branch on the line conductors. C 301 and C 302 which lead to

  <Desc / Clms Page number 39>

 power line switchgear 394 and interrupts, at contacts 384, the circuit previously drawn for the application of an earth potential via the upper winding of the tone relay R 390 to the control conductor C 223 of junction 225;

   on the other hand, said relay closes, aux. contacts 383, the circuit previously drawn for the application of a battery potential, through the intermediary of the impedance 257, to the control conductor C 223 of the junction 225, so that the tone relay R 390 releases its frame.

   When the earth potential which was applied to the control conductor C 223 of the junction 225 is thus replaced by a battery potential, the selector finder junction 203 is released and the junction 225 is indicated as free to the selectors of the selector finder joints 203, etc .... who have access to said junction. when the seeker-selector junction 203 is thus released, the line circuit 213 operates and indicates to the city connectors 205, etc. which have access to the subscriber line 211 terminating at the subscriber station T II that said position is free.



   When the signal output relay R 397 of the power line carrier 394 releases its armature, it interrupts, at contacts 398, the anode circuit of the associated transmission amplifier, so that the carrier signal at 24, 55 kilocycles is thus eliminated from line 60. When the carrier signal at 24.55 kilocycles is thus eliminated from line 60, the carrier current equipment 494 responds by producing a new energization of the signal input relay R 495 of said signal input relay. equipment.

   By pulling its armature again, the signal input relay R 495 of the power line carrier 494 interrupts, at contacts 496, the circuit previously indicated for the application of an earth potential to the conductor of. signal input C 404 which causes de-energization of the signal input relay R 450 of the junction circuit 400. By releasing its armature, the signal input relay R 450 interrupts; to contacts 451,

  <Desc / Clms Page number 40>

 the loop circuit previously drawn between the right winding of the response relay R 445 and the junction 435, so that the city connector 427 and the arrival selector 429 included in said loop circuit are released.

   When the urban connector 427 is thus released, the line circuit 423 is actuated so as to indicate to the utbains connectors 427 etc. which have access to the subscriber line 421 terminating at the subscriber station T 21 that said station is free. when the arrival selector 429 is thus released, the junction 428 leading to the urban connector 427 is indicated as free to the arrival selectors 429 etc ... which have access to said junction.



  In addition, when the arrival selector 429 is thus released, the earth potential of said selector is removed from the C control conductor 438 of the junction 435, which interrupts the multiple circuits previously drawn for the excitation of the. left winding of the response relay R 445 and of the lower winding of the switching relay R 460. In addition, by releasing its armature, the signal input relay R 450 interrupts, at contacts 452, the previously drawn circuit which maintained energized the bonding relay R 400, so that the latter relay releases its armature a short time later, being determined that it is of the delayed release type.

   By releasing its armature, the bonding relay R 400 interrupts, at contacts 405, the circuit previously drawn for the excitation of the upper winding of the switching relay R 460, in such a way that the latter releases its armature. By releasing its armature, the switching relay R 460 interrupts, at contacts 467, the circuit previously drawn for the application of an earth potential to the control conductor C 433 of junction 430, and closes, at contacts 466, the circuit. circuit previously drawn for the application of a battery potential, via the impedance 458 to the C control conductor 433, so that the junction 430 is indicated as free at the arrival selectors 434 etc. ..,

   and the junctions selectors

  <Desc / Clms Page number 41>

 selector searcher 426, etc ... which have access to said juncticn.



   At this moment, the communication established between the calling subscriber station T II of the remote exchange 10 and the called subscriber station T 21 of the tandem exchange 20 is interrupted and all the devices involved in said communication are completely released and become available. for later use.



   From the foregoing, it will be readily understood that a communication can be established in an identical manner between a calling subscriber station T II etc ... of the remote exchange 10 and a requested prepaid station T 22. , etc ... of the tandem exchange 20. It will also be understood that a call originating from a prepaid calling station T 12, etc ... from the remote exchange 10 can be routed to a called subscriber station T 21 , etc ... or to a requested prepayment station T 22, etc ... of the tandem exchange 20, in a substantially identical manner.

   In this area, it will be noted, with regard to the establishment of a communication between the requesting prepayment station T 12 of the remote exchange 10 and a requested subscriber station or a prepaid station requested from the taidem exchange 20, that , when the call is answered, the device operates in such a way as to energize the battery reversing relay R 240 of the junction circuit 200, so that the polarity of the junction 225 is reversed with respect to the upper and lower windings of the line relay R 330 of the junction circuit 200, all in the manner previously explained.

   This polarity reversal on junction 225 and on a seeker-selector junction, such as for example the seeker-selector junction 203 and on line 212 terminating at the T 12 prepayment station causes the transmitter to lock up. prepayment station T 12 by the associated copper oxide rectifier, unless the person wishing to use the prepayment station T 12 has introduced at this time in this device the necessary token.

   More precisely, in the event that the person who wishes to use the requesting prepaid set T 12 has not entered at this time

  <Desc / Clms Page number 42>

 token, it can hear the person who goes off hook at the subscriber set or at the prepaid set requested from the tandem exchange 20, but it cannot enter into a conversation with the latter due to the fact that the oxide rectifier of copper blocks the associated emitter following the inversion of the polarity at the T 12 prepayment station. On the other hand, when the person using the T 12 prepayment station inserts a token into the device, the rectifier with copper oxide no longer blocks the emitter of said apparatus, so that communication is established in the manner described above.

   



   CALL FROM A SUBSCRIBER SET OR A SET PREVIOUSLY FROM THE REMOTE CENTRAL 10 AND DESTINATIONS. AT
PRINCI OFFICE OPERATOR SWITCH PANEL
PAL 40.



   Assume first that a call initiated by a subscriber station such as, for example, the subscriber station T II of the remote exchange 10 is to be routed to the operator switchboard 765 in the office. main 40. It will be assumed, on the other hand, that the searcher of the searcher-selector junction 203 has attacked the subscriber line 211 terminating at the calling subscriber station T II and that the selector of the searcher-selector junction 203 is packaged in such a way that it is sensitive to the first digit formed on the call dial.

   The subscriber of the calling subscriber station T II of the remote exchange 10 then forms on his dial the two digits designated as the call numbers of the operator switch board 765 of the main office 40; these two digits can * be for example "0" and "0". When the first digit "0" is formed on the dial of the calling subscriber station T II of the remote exchange 10, the selector of the searcher-selector junction 203 selects in response an associated bundle of junctions comprising in particular junction 220, then in said beam

  <Desc / Clms Page number 43>

 a free jonotion.

   For example, the selector of the selector finder junction 203 can select the particular junction 220 leading to the junction circuit 200. The junction 220 being indicated as free by the application of a battery potential through the circuit previously. plot including the impedence 257 to the control conductor C 223.



  In addition, when the selector of the seeker-selector junction 203 drives the junction 220, a loop circuit is closed for the series energization of the upper and lower windings of the line relay R 330 and the upper winding of the line relay. R 250 series relay in junction circuit 200.



   More precisely, an earth potential is applied, through the contacts 362 of the lower winding of the line relay R 330, to the line conductor C 222 of the junction 220, and a battery potential is applied, through the 'intermediate the upper winding of line relay R 330, to line conductor C 221 of junction 220. When the loop circuit is thus closed, the line relay R 330 and the series relay R 250 are both excited. When operating, line relay R 330 closes, at contacts 331, the circuit previously indicated for energizing the R 380 bonding relay.

   While operating, the bonding relay R 380 interrupts, at contacts 381, the termination circuit previously drawn comprising the resistor 344 and the capacitor 286, as well as the capacitors 347 and 348 in shunt on the line conductors C 301 and C 302 terminating to powerline carrier equipment 394.

   In addition, the bonding relay R 380 interrupts, at contacts 383, the circuit previously drawn for the application of a battery potential, by means of the impedance 257 to the control conductor C 223 of junction 220 and closes, at oontacts 384, the circuit previously drawn for the application of an earth potential, via the upper winding of the tone relay R 390, to the conductor.

  <Desc / Clms Page number 44>

 control tower C 223 of junction 220, so that the tone relay R 390 attracts its armature and junction 220 is indicated as occupied - to the selectors of the other seeker-selector junctions which have access to said junction 220 .

   When operating, the series relay R 250 firstly closes, at contacts 252, a bonding circuit passing through contacts 382 for energizing the lower winding of said relay then closes, at contacts 251, a circuit obvious for short-circuiting the upper winding of said relay, so that a single loop circuit is established between the calling subscriber station T II and the line relay R 330.

   On the other hand, the line relay R 330 causes the energization of the signal output relay R 397 of the power line carrier 394 and this last relay causes the release of the armature of the signal input relay R 395 of power line carrier 494, so that the signal input relay R 450 of junction circuit 400 is energized, all in the manner previously discussed. When operating, the signal input relay R 450 causes the sticking relay 400 to be energized.

   While operating, the sticking relay R 400 causes the excitation of the switching relay R 460 which, when operating, drives the arrival selector 429 via the junction 435, so that the arrival selector 429 is conditioned in such a way that it be sensitive to the next digit formed on the call dial of the calling subscriber station T II of the remote exchange 10, all in the manner described above.



   The subscriber of the calling subscriber station T II of the remote exchange 10 then proceeds to form on his dial the second digit "0" of the call number called the operator switch table 765 of the main office 40, so that the Line relay R 330 of junction circuit 200 operates accordingly and retransmits the corresponding impulses at contacts 333 to signal output relay R 397 of power line carrier 394.

   The signal output relay R 397 retransmits the digit

  <Desc / Clms Page number 45>

 "0" to contacts 398 on line 60 to the signal input relay
R 495 of powerline carrier switchgear 494. Signal input relay R 495 retransmits the number T'On to contacts 496, to signal input relay R 450 of junction circuit 400 and relay d 'signal input R 450 retransmits, to the contacts
451, the number "0" from junction 435 to the arrival selector
429, all in the manner explained above.



   During the transmission of the pulses, the number relay R 320 of the junction circuit 200 is energized and closes, at contacts 324, the variant termination circuit passing through resistor 344 and the capacitor 286 in shunt on the conduc - Line Teurs C 301 and C 302 which lead to the carrier current equipment 394, as explained above.

   In addition, in operation, the number relay R 320 closes to contacts 325 a circuit passing through contacts 382, 245, 254, 363, and 373 for the energization of the lower winding of the number relay.
R 370 and a substantially identical circuit also passing through contacts 377 and 367 and resistor 345 for the excitation of the upper winding of the number relay R 370, so that the latter relay performs the first phase of its operation given that it is of the stepped action type. By performing the first phase of its staggered operation, the number relay R 370 closes, at contacts 375, a circuit passing through contacts 373, 363, 325 and 365 and shorting the upper winding of said relay.

   In addition, during the transmission of the pulses, the numbering relay R 455 of the junction circuit 400 is energized as indicated above and closed, at contacts 457, the circuit previously drawn comprising the resistor.
454, and short circuit the right winding of response relay R 445.



   The arrival selector 429, in response to the number "0", selects the junction bundle comprising in particular the junction 515 then, in said bundle, a free junction. For example, the selector

  <Desc / Clms Page number 46>

 arrival 429 can select the particular junction 515 terminating at the junction circuit 500. The particular junction 515 being indicated as free by the application of a battery potential on its control conductor C 513, through the intermediary of contacts 578 and 639 and through resistor 617 a loop circuit is also closed between the right winding of the response relay R 445 of the junction circuit 400 and the upper and lower windings of the line relay R 610 of the junction circuit 500.

   This loop circuit is established as follows: earth, lower winding of line relay R 610, contacts 634, winding 652 of the RC 650 tranelator and contacts 532, line conductor C 516, of junction 515 and battery, upper winding of the relay line conductor R 610, oontacts 632, winding 651 of translator RC 650, contacts 534, line conductor C 517 of junction 515. Line conductors C 516 and C 517 of junction 515 are connected via re from incoming selector 429 to line conductors C 436 and C 437 of junction 435.

   The last conductors of the indicated line are connected via contacts 463 and 451 to the upper and lower terminals of the right winding of the rethinking relay R 445. However, the right winding of the response relay R 445 is at this time short-circuited through contacts 457 and resistor 454, so that only the upper and lower windings of the line relay R 610 of the junction circuit 500 are energized at this time.



   A short time after the end of the formation on the dial of the calling subscriber station T II of the second digit "O", the numbering relay R 320 of the junction circuit 200 releases its armature, since it is of the delayed release type as previously explained, by interrupting, at contacts 324, the additional termination circuit previously drawn comprising the resistor 344 and the capacitor 286 in bypass on the line conductors C 301 and C 302 which terminate at the equipment

  <Desc / Clms Page number 47>

 powerline carrier 394.

   Moreover, by releasing its armature, the numbering relay R 320 interrupts, at contacts 325, the circuit previously drawn which short-circuited the upper winding of the number R 370 relay, so that the upper and lower windings of said relay are excited in series by a circuit passing through the contacts, 375, 365, 254, 245, and 382, which causes the relay to accomplish the number R 370 the second phase of its staggered operation.

   when the number relay R 370 performs the second phase of its staggered operation, it interrupts, at contacts 377, a point of the circuit previously traced for the excitation of the upper winding of said relay in multiple with its lower winding and prepares, for contacts 376, a point of a substantially identical circuit traced below for the excitation of the lower winding of the number relay R 360, while preparing, at the contacts 374, a circuit traced later for the excitation in multiple of the upper and lower windings of the R 360 digit relay.



   In addition, a short time after the end of the formation on the dial of the calling subscriber station T II of the second digit "0", the dialing relay R 455 of the junction circuit 400 releases its armature, since it is of the delayed release type as previously explained and interrupts, at contacts 457, the circuit previously drawn for short-circuiting the right-hand winding of the response relay R 445, so that the right-hand winding of the response relay R 445 of the junction circuit 400 is excited in series with the upper and lower windings of the line relay R 610 of the junction circuit 500 by the previously traced loop circuit. However, at this moment, the direction of polarity of the response relay R 445 is not likely to ensure its excitation.



   When the upper and lower windings of the line relay R 610 are thus energized, the latter relay operates and closes, at contacts 614, - an obvious circuit for energizing the sticking relay R .570. When operating, the bonding relay

  <Desc / Clms Page number 48>

 R 570 closes, at contacts 575, a circuit passing through contacts 546 for the application of an earth potential to the starting conductor C 526 of the calling device, so as to trigger operation of the device associated call.

   In addition, the bonding relay R 570 interrupts, at contacts 578, the circuit previously drawn for the application of a battery potential, via the resistor 617, to the control conductor C 513 and closes, at contacts 577, an obvious circuit for the application of an earth potential, through the lower winding of the tone relay R 565, to the control conductor C 513, so as to cause the the energization of the tone relay R 565. When the battery potential which was applied to the control conductor C 513 of the junction 515 is thus replaced by a ground potential, the junction 515 is indicated as occupied to the arrival selectors 429, etc .... who have access to said junction.

   In addition, the bonding relay R 570 closes, at contacts 576, an obvious circuit for the excitation of the lower winding of the control relay R 590, in such a way that the latter relay attracts its armature.



   It will be observed here that a circuit is normally closed to keep the drive relay R 585 energized in the junction circuit 500. This normally closed circuit is established as follows: battery, winding of the drive relay R 585, contact 592, simplex between windings 653 and 654 of translator RC 650 of junction circuit 500 and earth, contacts 661 and 671, copper oxide rectifier 666, simplex between windings 676 and 677 of translator R 675 of junction circuit 600. The simplex of the RC 650 translator is connected, through the windings 653 and 654 of said translator, by the line conductors of the junction line 665 which connects the tandem exchange 20 to the repeater 30 and by the windings 676 and 677 of the translator RC 675, at the simplex of said translator.

   The copper oxide rectifier 666 of the junction circuit 600 is mounted in such a way that it passes the current in the direction

  <Desc / Clms Page number 49>

 indicated, so that the winding of the drive relay R 585 of the junction circuit 500 is normally energized and the latter relay is normally energized.

   While operating, the control relay R 590 interrupts, at contacts 592, the normally closed circuit traced above which kept the attack relay R 585 actuated and closes, at contacts 593, a circuit passing through contacts 612 for the application. a positive potential from the overvoltage battery 616, through the lower winding of the pulse relay R 620 at the simplex between the windings 653 and 654 of the translator RC 650 of the junction circuit 500, so that the current passes through the junction line 665 to the siplex between the windings 676 and 677 of the tanslator RC 675 of the junction circuit 600 and is conducted from there,

   via the copper oxide rectifier 667 of the lower winding of the signal output relay R 660 and contacts 672 to earth. Note that the copper oxide rectifier 667 is mounted in such a way that it passes the current from the surge battery 616 of the junction circuit 500 over the junction line 665 and through the winding. bottom of signal output relay R 660 of junction circuit 600.

   As a result, the lower winding of the pulse relay R 620 of the junction circuit 500 is energized in series with the lower winding of the signal output relay R 660, of the junction circuit 600, serving only said relays - are operating, the R 620 pulse relay being of the marginal type.



   In addition, while operating, the bonding relay R 570 closes, at contacts 574, a circuit passing through contacts 543, 544 553 for the application of an earth potential to the line conductor C 512 of junction 510 and, therefore, through contacts 532 to line conductor C 516 of the

  <Desc / Clms Page number 50>

   junction'515. In addition, the bonding relay R 570 closes, at contacts 571, a circuit passing through capacitor 624, contacts 641, 561 and 551 and capacitor 525 for the connection of conductor C 623 of the generator to line conductor C 511 of the junction 510 and consequently through the contacts 534, to the line conductor C 517 of the junction 515.



  In this manner, a current called calling party warning tone stream is returned from trunk 500 to trunk 515 and from there through inbound selector 429, trunk 435 and previously drawn circuit including line conductors C 401 and C 402 to powerline carrier 494. Calling party alert tone current of called called party causes the apparatus to operate. carrier 494 from central office to tandem 20, so that the carrier signal at 15.95 kilocycles is modulated by said tone and applied through line 60 to carrier current apparatus 394 at remote exchange 10.

   The powerline carrier apparatus 394 operates correspondingly and causes the calling party warning tone current of the called party to be returned to the previously traced circuit including the C 301 line conductors. and C 302 at the calling subscriber station T II, so as to indicate to the subscriber of said station that the operator is called.



   While operating, the signal output relay R 660 of the junction circuit 600 interrupts, at contacts 661, the previously traced circuit which applied a direct earth potential through the contacts 671 and the copper oxide rectifier 666 at the simplex between windings 676 and 677 of the RC 675 translator. However, this application has no effect at this time since the positive potential coming from the surge battery 616 of the junction circuit 500 cannot pass through the oxide rectifier of copper 666 of the junction circuit 600 in the direction shown.

   In addition, the R 660 signal output relay closes a circuit at contacts 662

  <Desc / Clms Page number 51>

 variant passing through the contacts 671 and the copper oxide rectifier 666 for the application of an earth potential via the upper winding of said relay at the simplex between the windings 676 and 677 of the transformer RC 675. This application is, however, ineffective as the copper oxide rectifier 666 does not pass current in the direction indicated from the surge battery 616 to the junction circuit 500.



  In addition, the signal output relay R 660 of the junction circuit 600 closes at contacts 663 a circuit for the application of an earth potential to the signal output conductor C 603, which causes the energization of the R 697 signal output relay in powerline carrier switchgear 694.



   When operating, the signal output relay R 697 closes at contacts 698, the anode circuit of the associated transmit amplifier, so that the carrier signal at 24.55 kilocycles is transmitted from the carrier current equipment. 694 from repeater 30 on line 70 to powerline carrier 794 at main office 40. Powerline carrier 794 responds to the 24.55 kilocycles carrier signal transmitted to it and causes the carrier to release. armature of the signal input relay R 795 so that the latter relay closes, at contacts 796, an obvious circuit for the application of an earth potential to the signal input conductor C 704 so as to energize the lower winding of the R 705 signal input relay of the 700 junction circuit.

   A short time after the lower winding of the signal input relay R 705 is thus de-energized, the latter relay operates, since its operation is slightly delayed due to the normally closed circuit passing through contacts 715 and short. -circuitant the upper winding of said relay. When operating, the R 705 signal input relay closes a circuit at contacts 707

  <Desc / Clms Page number 52>

 obvious for switching on the occupancy lamp L 732 and a multiple visible circuit through contacts 714 for switching on the line lamp L 733.

   The switching on of the busy lamp L 732 indicates to the operator of the switchboard 765 that the junction circuit 700 is busy at this moment, while the switching on of the line lamp L 733 indicates to the said operator. that a call is pending on trunk 700 at this time.



   By observing the switch-on condition of the line lamp L 733, the operator of the operator switch panel 765 selects a free dicord such as dicorde 766 and inserts the front plug P 748 of said dicorde into jaok J 730 which ends the junction circuit 700. When the front plug P748 is thus plugged into the J 730 jack, the contacts 731 of said jack are closed and complete an obvious circuit for the energization of the R 710 jack relay. Likewise, the body of the front plug P 748 engages the plug body of the jaok J 730 by closing a series circuit passing through contacts 741 for energizing the lower winding of the plug relay R 720 in the junction circuit 700 and the winding of the front monitoring relay R 745 in the dicorde 766.

   When said series circuit is closed, plug relay R 720 operates.



  On the other hand, the R 745 stop monitoring relay does not work, since it is of the marginal type. The operator of the operator switch panel 765 also activates the front conversation key 2: 734 of the dicorde 766 so as to bypass the operator's station or headset 767 of the dicorde on the tip and loop wires of the plug. before P 748.

   While operating, the plug relay R 720 interrupts, at contacts 725, a normally closed terminating circuit comprising the resistor 717 in shunt on the line conductors C 701 and C 702 which terminate in the powerline carrier equipment 794

  <Desc / Clms Page number 53>

 and establishes, at contacts 723 and 726 a direct connection between the tip and the loop of the jack J 730 and the line conductors
C 701 and C 702 which terminate at powerline carrier equipment 794, so that the headset 767 of the switchboard 765 is connected via the line conductors C 701 and C 702 to the apparatus carrier current 794 at this time.



   On the other hand, while operating, the plug relay R 720 closes, at the contacts 721, a circuit passing through the contacts 711 for the application of a battery potential, via the resistor 709, to the conductor of signal output C 703 so as to cause the operation of the signal output relay R 797 in the powerline carrier equipment 794, so that the latter relay closes the contacts 798 of the anode circuit of the associated transmit amplifier , which results in the transmission of the carrier signal at 15.95 kilocycles from the carrier current apparatus 794, via line 70 to the carrier current apparatus 694 of the repeater 30. - carrier current line 694 of repeater 30 responds to the carrier signal at 15,

  95 kilocycles by causing the armature of the signal input relay R 695 to release, so that the latter relay interrupts, at contacts 696, a normally closed circuit for the application of a battery potential to the conductor of signal input C 604, so as to release the armature of the signal input relay R 670 in the junction circuit 600.

   By releasing its armature, the signal input relay R 670 interrupts, at contacts 672, the circuit previously transferred for the excitation of the lower winding of the signal output relay R 660 in the junction circuit 600 in series with the lower winding of the pulse relay R 620 in the junction circuit 500 and closes, at contacts 673, a circuit of substantially identical variant for the excitation

  <Desc / Clms Page number 54>

 connection in series of the intermediate and lower windings of the signal output relay R 660 and of the lower winding of the pulse relay R 620. When said additional series circuit is thus closed, the signal output relay R 660 of the circuit junction 600 is maintained in its energized position.

   On the other hand, the pulse relay R 620 of the junction circuit 500 releases its armature, given that it is of the marginal type.



   By releasing its armature, the pulse relay R 620 of the junction circuit 500 closes, at contacts 622, a bonding circuit passing through contacts 586 for energizing the upper winding of control relay R 590 and a branch circuit passing through contacts 594 for energizing the monitoring relay R 560.

   When operating, the monitoring relay R 560 interrupts, at contacts 561, the circuit previously drawn for the connection of the conductor C 623 of the interrupting generator to the line conductor C 517 of junction 515, which stops the circuit. forwarding of the calling party warning tone current of the called party's call to the calling subscriber station T II of the remote exchange 10. In addition, the monitoring relay R 560 closes at contacts 562, a circuit passing through contacts 573 and 542 for energizing the time relay R 550.



  While operating, the time relay R 550 interrupts, at contacts 551, another point of the connection previously drawn between the conductor C 623 of the interrupting generator and the line conductor C 517 of junction 515 and interrupts, at contacts 553, the circuit previously traced for the application of a potential, of earth to the line conductor C 516 of the junction 515.



  In addition, the time relay R 550 closes, at contacts 552 and 554, a circuit passing through the capacitor 525 for the bypassing of the upper winding of the tone relay R 565 on the line conductors C 511 and C 512 of junction 510. Said conductors are connected to the upper terminals

  <Desc / Clms Page number 55>

 and lower windings 651 and 652 of the RC 650 translator, the lower terminals of the windings 651 and 652 being connected to each other by the capacitor 655,

   so that any tone current induced in the upper winding of the R 565 tone relay from the lower winding of said relay passes through the windings 651 and 652 of the RC 650 translator and is returned to the switchboard operator 765 for a purpose which will be discussed in more detail later. In addition, any tone voltage appearing between line conductors C 516 and C 517 of junction 515 is applied, through contacts 532 and 534, to line conductors C 512 and C 511 of junction 510. and, accordingly, passes through the windings 651 and 652 of the RC translator 650 and is returned to the operator of the switch board 765 for a purpose which will be discussed later in more detail.

   It will be observed that $ ci that no tone current is returned to the operator at switchboard 765 at main office 40 following the answer to the call under consideration, since this call was made at the telephone set. calling subscriber! .... from the remote exchange 10.



   In operation, the time relay R 550 also causes the vibration of its RA 555 armature, so that the associated contacts 556 are closed intermittently and produce a corresponding energization of the winding of the time relay R 540. However, this last relay does not attract its frame at this time, as it is of the delayed release type.



  After a short time interval, the armature RA 555 of the time relay R 550 stops vibrating and closes, at contacts 556, the circuit indicated for the energization of the winding of the time relay R 540, in such a way that this last relay attracts its armature. While operating, the time relay R 540 closes, at contacts 541, a bonding circuit passing through contacts 573

  <Desc / Clms Page number 56>

 and 562 for energizing the winding of said relay and interrupts, at contacts 542, the previously drawn circuit which kept the time relay R 550 energized.

   By releasing its armature, the time relay R 550 interrupts, at contacts 552 and 554, the previously traced circuit updates the bypass of the upper winding of the tone relay R 565 on the line conductors C 511 and C 512 of junction 510, thereby terminating the return of the tone to the operator switch panel 765 of the main office 40 in the event that a tone voltage is induced in the upper winding of the tone relay R 565 by the lower winding of said relay.



  On the other hand, the time relay R 540 interrupts, by operating, at contacts 546, the circuit previously drawn for the application of an earth potential to the starting conductor C 526 of the call device, which stops the operation of said device and closes, at contacts 545, a bonding circuit passing through contacts 575 and now energized bonding relay R 570. Finally, time relay R 540 closes, at contacts 544, a circuit passing through contacts 622 for energizing the battery reversing relay R 530, so that this last relay inverts, at contacts 531, 532, 533 and 534, the polarity of the line conductors C 516 and C 517 in relation to the upper and lower windings of the R 610 line relay.

   When the polarity of junction 515 is reversed on arrival selector 429 and on junction 435, the right winding of response relay R 445 of junction circuit 400 is biased such that said relay is energized. .



   While operating, the response relay R 445 interrupts, at contacts 446, the previously traced termination circuit comprising the resistor 444 and the capacitor 443 in shunt on the line conductors C 401 and C 402 which terminate in the power line switchgear. 494 and cause the R 440 monitoring relay to be energized. The R 440 monitoring relay

  <Desc / Clms Page number 57>

 itself causes the energization of the signal output relay R 497 of the power line carrier 494 and, consequently, the release of the armature of the signal input relay R 395 of the power line carrier 394, so that the signal input relay R 350 of the junction circuit 200 is energized all in the manner previously explained.

   When operating, the R 350 signal input relay generates the excitation of the R 340 bonding relay in the manner previously discussed. When operating, the bonding relay R 340 closes, at contacts 341, a circuit passing through contacts 385, 255 and 239 for the energization of the time relay R 280, so that this last relay closes, at contacts 282 and 283, a circuit passing through capacitor 286 and through capacitors 347 and 348 and bypassing the lower winding of tone relay R 390 on line conductors C 301 and C 302 which terminate in the pcrtor-current apparatus 394.

   In this way, any tone voltage induced in the lower winding of the tone relay R 390 by the tone current flowing through the upper winding of said relay is applied between the line conductors C 301 and C 302 and transmitted through the established connection. to main office 40 operator switch panel 765 for a purpose which will be discussed in more detail below. In the example considered here, no tone is transmitted by the connection established at the operator switchboard 765 of the main office 40, since the call considered at its origin at the calling subscriber station T II from the remote exchange 10.



   On the other hand, the time relay R 280 causes, in operation, the vibration of its armature RA 284, so that the contacts 285 associated with said relay are closed intermittently, causing intermittent energization of the winding. of the time relay R 235. However, this latter relay does not immediately attract its armature, since it is of the delayed traction type. After a short time, the reinforcement

  <Desc / Clms Page number 58>

 RA 284 of the time relay R 280 stops vibrating by stably closing the contacts 285, so that the time relay R 235 attracts its armature a short time later, since it is of the delayed attraction type .

   While operating, the time relay R 235 closes, at contacts 238, a bonding circuit passing through contacts 255, 341 and 385 for energizing the winding of said relay and interrupts, at contacts 239, the circuit. previously traced which kept actuated the time relay R 280. By releasing its armature, the time relay R 280 interrupts, at contacts 285, the original circuit previously traced for the energization of the time relay R 235 However, this last relay remains in its working position due to the closure of the bonding circuit previously drawn for said relay.

   In addition, by releasing its armature, the time relay R 280 interrupts, at contacts 282 and 283, the circuit which bypassed the lower winding of the tone relay R 390 on line conductors C 301 and C 302. resulting in powerline carrier switchgear 394. The timing relay R 235 causes the battery reversing relay R 240 to be energized in the manner previously discussed. The operation of the battery reversal relay R 240 has no effect with regard to the polarity reversal on junction 220. Consequently, the polarity between the calling subscriber station! ..- il and the relay line R 330 of the junction circuit 200 is not reversed at this time.

   On the other hand, while operating, the battery reversing relay R 240 interrupts, at contacts 245, the previously traced circuit which kept the number R 370 relay energized, so that the latter relay releases its armature but has no effect. this moment. In addition, while operating, the time relay R 235 closes, at contacts 236, a bonding circuit passing through contacts 382 and 253 and now energizing the bonding relay R 380.



     At this time, a communication is completely established between

  <Desc / Clms Page number 59>

 the calling subscriber station T II of the remote exchange 10 and the called operator switchboard 765 of the main office 40.



  When an acoustic signal is emitted by the requesting subscriber station T 11, it is transmitted over the previously traced circuit comprising the conductors of, line C 301 and C 302, to the powerline carrier equipment, 394 of the remote central 10, so that the powerline carrier 394 operates by transmitting the lower sideband of the carrier signal at 24.55 kilocycles (21.7 to 24.3 kilocycles) on line 60. carrier current 494 of the tandem exchange 20 receives the lower lateral band of the carrier signal at 24.55 kilocycles - (21.7 to 24.3 kilocycles), it operates by transmitting the acoustic component of said band on the junction 435,

   the arrival selector 429 and the junction 515 to the windings 651 and 652 of the translator RC 650 of the junction circuit 500 of the central unit in tandem 20. The acoustic signal passing through the windings 651 and 652 of the translator RC 650 induces a corresponding acoustic signal - Dant in the windings 653 and 654 of said translator, and this signal is transmitted, via the junction line 665, to the windings 676 and 677 of the translator RC 675 of the junction circuit 600 of the repeater 30.

   The acoustic signal passing through the windings 676 and 677 of the RC 675 translator induces a corresponding acoustic signal in the windings 678 and 679 of said translator, and this signal is conducted through the C line conductors 601 and 602 to the current equipment carrier 694 of the repeater 30, so that the carrier current apparatus 694 operates to transmit the lower sideband of the carrier signal at 24.55 kilocycles (21.7 to 24.3 kilocycles) over line 70 to powerline carrier 794 at main office 40.

   When the main office 40 carrier 794 switchgear receives the lower sideband of the carrier signal at 24.55 kilocycles (21.7 to 24.3 kilocycles) it operates to transmit the acoustic component of said bard, on the circuit previously drawn including the

  <Desc / Clms Page number 60>

 line conductors C 701 and C 702, the jack J 730 and the front plug P 748 of the dicorde 766, to the headset 767 of the operator switch board 765.

   Similarly, when an acoustic signal is emitted by the operator station 767 of the operator switch panel 765 of the main office 40, it is transmitted through the previously traced circuit comprising the front plug P 748 of the di - rope 766, jack J 730 and line conductors C 701 and C 702 to the powerline carrier 794 at main office 40, so that the powerline carrier 794 operates to transmit the lower sideband of the carrier signal to 15.95 kilocycles (13.1 to 15.7 kilocycles) on line 70.

   When the power line switchgear 694 of the repeater 30 receives the lower sideband of the carrier signal at 15.95 kilocycles (13.1 to 15.7 kilocycles), it operates to transmit the acoustic component of said band onto the ring. - previously traced fired comprising the line conductors C 601 and C 602, the translator RC 675 of the junction circuit 600 of the repeater 30, the junction line 665 connecting the repeater 30 to the tandem exchange 20, the translator RC 650 of the junction 500 of the tandem exchange 20, junction 515, the incoming selector 429, the junction 435 and the line conductors C 401 and C 402 to the powerline carrier 494 of the tandem exchange 20,

   so that said carrier current apparatus 494 operates to transmit the lower sideband of the carrier signal at 15.95 kilocycles - (13.1 to 15.7 kilocycles) on line 60. when the apparatus carrier 394 of the remote exchange 10 receives the lower sideband of the carrier signal at 15.95 kilocycles (13.1 to 15.7 kilocycles) it operates in such a way as to transmit the acoustic component of said band on the circuit previously traced comprising the line conductors C 301 and C 302 at the calling subscriber station T II.



   The operator of the requested switch panel 765 of the main office 40 is informed by the subscriber of the requested subscriber station.

  <Desc / Clms Page number 61>

 deur T II of the remote exchange 10 with regard to the routing of the call. Said operator then proceeds to the routing of the call using the rear plug P 758 of the dicorde 766 in a manner which will be explained later in a more detailed form.



  * At the end of the established call, when the subscriber of the calling subscriber station T II of the remote exchange 10 hangs up, the loop circuit previously drawn between the calling subscriber station T II and the line relay R 330 of the junction circuit 200 is interrupted, so that the latter relay releases its armature. By releasing its armature, the line relay R 330 opens, at contacts 331, the original circuit for the excitation of the bonding relay R 380. However, the latter relay remains maintained in its working position due to the closing of the circuit. bonding ensuring the excitation of these windings.



  On the other hand, by releasing its armature, the line relay R 330 interrupts, at contacts 333, the circuit previously indicated for the application of an earth potential to the signal output conductor C 303, so as to cause the armature of the R 397 signal output relay of the power carrier switchgear 394 to release and therefore re-operate the R 495 signal input relay of the switchgear 494, which is resulting in the release of the armature of the signal input relay R 450 in the junction circuit 400, all in the manner explained previously.

   By releasing its armature, the R 450 signal input relay interrupts, at contacts 452, the previously indicated circuit which kept the R 400 bonding relay energized, so that the latter relay releases its armature a short time later. , since it is of the delayed release type. On the other hand, the signal input relay R450 closes, at the contacts 453, a bonding circuit passing through the contacts 468 and 441 for the energization of the lower winding of the monitoring relay R 440.

   Finally,

  <Desc / Clms Page number 62>

 the signal input relay R 450 interrupts, at contacts 451, the loop circuit previously drawn between the right winding of the response relay R 445 in the junction circuit 400 and the line relay R 610 in the junction 500, so that the two indicated relays release their ammature.



  By releasing its armature, the response relay R 445 closes, at contacts 446, the previously drawn termination circuit comprising resistor 444 and capacitor 443 in shunt on the line conductors C 401 and C 402 which terminate at the powerline carrier 494 and interrupts, at contacts 447, the circuit previously drawn for the excitation of the upper winding of the monitoring relay R 440. However, the latter relay is maintained in its operating position due to the closing of the bonding circuit ensuring the excitation of its lower winding. By releasing its armature, the line relay R 610 of the junction circuit 500 interrupts, at contacts 614, the original circuit previously drawn for the excitation of the bonding relay R 570.

   However, the latter relay is maintained in its actuating position at this time due to the closing of its bonding circuit passing through contacts 575 and 545.



  In addition, the line relay R 610 interrupts, at contacts 612, the circuit previously drawn for the excitation of the lower winding of the pulse relay R 620 and the intermediate and lower windings of the signal output relay R 660 in the junction circuit 600 in series and closes, at contacts 613, a variant circuit passing through contacts 582 and 593 for the application of a battery potential via the upper winding of the relay. R 620 pulses at the simplex between the windings 653 and 654 of the RC 650 translator. The R 620 pulse relay remains de-energized and the R 660 signal output relay releases its armature since the copper oxide rectifier 667 n is not polarized so as to allow current to flow in the direction indicated.

   When releasing its armature, the R 660 signal output relay interrupts,

  <Desc / Clms Page number 63>

 at contacts 663, the circuit previously drawn for the application of an earth potential to the signal output conductor C 603, which causes the armature of the signal output relay R 697 to release in the current equipment carrier 694. By releasing its armature, the signal output relay R 697 opens the contacts 698 included in the anode circuit of the associated transmission amplifier, so that the carrier current device 694 eliminates the signal. carrier at 24.55 kilocycles from line 70.

   After this elimination, the powerline carrier equipment 794 of the main office 40 responds so as to cause a new energization of the signal input relay R 795, so that the latter relay interrupts, at contacts 796, the previously circuited circuit. trace for the application of an earth potential to the signal input conductor C 704 so as to de-energize the lower winding of the signal input relay R 705 in the circuit junction 700. The relay of signal input R 705 releases its armature by interrupting, at contacts 707, the circuit previously drawn for switching on the occupancy lamp L 732. However, this last lamp is kept on by the jack relay R 710 which is excited at this time.

   In addition, the signal input relay R 705 closes, at contacts 706, a circuit passing through oontacts 712 and 741 and through the plug bodies of the J 730 jack and the front plug P 748 for the excitation of the upper winding of the plug relay R 720 in series with the winding of the monitoring relay R 745. the plug relay R 720 of the junction circuit 700 is already in its energized position and the front monitoring relay R 745 of the dicorde 766 works since it is of the marginal type.

   While operating, the front monitoring relay R 745 closes, at contacts 746, an obvious circuit for the ignition of the front monitoring lamp L 747 so as to indicate to the operator of the switch panel 765 that the subscriber of the calling subscriber station T II of the remote exchange 10 has hung up.

  <Desc / Clms Page number 64>

 



   When the operator of the switchboard 765 of the main office 40 receives the end of conversation signal, she removes the front plug P 748 of the dichord 766 from the J 730 jack which terminates the junction circuit 700, which interrupts the circuit previously. layout for energizing the winding of the front monitoring relay R 745 of the dicorde 766 in series with the upper and lower windings connected in parallel with the plug relay R 720 in the junction circuit 700, so that said relays release their armature.

   In addition, when the front plug P 748 of dicorde 766 is removed from jack 730, contacts 731 are opened, which interrupts the circuit which kept the jack relay R 710 in the junction circuit 700 activated, so that the latter relay releases its frame a short time later, since it is of the delayed release type. By releasing its amature, the avmt R 745 monitoring relay interrupts, at contacts 746, the circuit previously drawn for the ignition of the front monitoring lanpe L 747. By releasing its armature, the R 710 jack relay interrupts, at contacts 713, the previously traced circuit for switching on the occupancy lamp L 732, which indicates that the junction circuit 700 is free at this time.

   By releasing its amature, the plug relay R 720 interrupts, at contacts 723 and 726, the connection between the tip and the loop of the jack J 730 and the line conductors C 701 and C 702 which lead to the device. current carrier 794 and closes, at contacts 725, the terminal circuit, its previously indicated comprising the resistor 717 in shunt on line conductors C 701 and C 702. On the other hand, said relay interrupts, to the contacts 721, the circuit previously drawn for the application of a battery potential, via the resistor 709, to the signal output conductor C 703, so as to cause the de-energization of the relay of R 797 signal output from powerline carrier 1 age 794.

   By releasing its armature, the relay

  <Desc / Clms Page number 65>

 signal output R 797 opens the contacts 798 included in the anode circuit of the associated transmit amplifier, so that the carrier current equipment 794 eliminates the carrier signal at 15.95 kilocycles from line 70, in such a way that the carrier current apparatus 694 of the repeater 30 causes the re-energization of the signal input relay R 695 of said apparatus, so that the latter relay closes, at the contacts 696, the circuit previously drawn for the application of a battery potential to the signal input conductor C 604 by causing the re-energization of the signal input relay R 670 in the junction circuit 600.

   By attracting its armature again, the signal input relay R 670 closes, at contacts 671, the previously traced circuit passing through contacts 661 and the copper oxide rectifier 666 for the application of a potential of earth at the simplex between the windings 676 and 677 of the RC 675 translator, so as to close a circuit also passing through the contacts 594, 613 and 582 for the excitation of the upper winding of the R 620 pulse relay in the circuit of junction 500. This last circuit indicated and closed at this time due to the fact that the copper oxide rectifier 666 is biased so as to pass current in the direction indicated, so that the pulse relay R 620 works.

   When operating, the pulse relay R 620 interrupts, at contacts 622, the circuits in parallel for energizing the upper winding of the control relay R 590 and for keeping the relay energized. R 530 battery changeover relay and R 560 monitoring relay. In this way, the R 530 battery changeover relay releases its armature immediately and the R 560 monitoring relay releases its own a short time later, since 'it is of the delayed release type. On the other hand, the control relay R 590 does not immediately release its armature due to the closing of the bonding circuit passing through contacts 576 of the actuated bonding relay R 570.

  <Desc / Clms Page number 66>

 for energizing the lower winding of said relay.

   By releasing its armature, the monitoring relay R 560 interrupts, at contacts 562, the bonding circuit previously traced which kept the time relay R 540 actuated, so that the latter relay, by releasing its armature, interrupts. at contacts 545 the previously traced bonding circuit which kept the R 570 bonding relay actuated. A short moment later, the R 570 bonding relay releases its armature given that it is of the delayed release type by interrupting, to contacts 576, the bonding circuit previously drawn for energizing the lower winding of control relay R 590, in such a way that the latter relay releases its armature a short instant later, given that it is of the delayed release type.

   On the other hand, by releasing its armature, the 8 570 sticking relay interrupts, at contacts 577, the circuit previously drawn for the excitation of the lower winding of the tone relay R 565 and for the application of '' an earth potential to the control conductor C 513 of junction 515, so that the tone relay R 565 releases its armature and the arrival selector 429 is released following the removal of the earth potential of control conductor C 513 of junction 515. By releasing its armature, control relay R 590 interrupts, at contacts 593, the circuit previously drawn for the excitation of the upper winding of pulse relay R 620 , in such a way that the latter relay releases its armature and closes, at contacts 592,

   the original circuit previously drawn for the excitation of the R 585 drive relay.



   When the arrival selector 429 is thus released, the earth potential is eliminated from the control conductor C 438 of the junction 435, which de-energizes the left winding of the response relay R 445 and the lower winding of the response relay. switching relay R 460 in junction circuit 400. In this way the switching relay R 460 releases its armature, the switching relay

  <Desc / Clms Page number 67>

 response R 445 being already de-excited at this time. By releasing its armature, the switching relay R 460 interrupts, at contacts 468, the bonding circuit previously drawn for the energization of the lower winding of the R 440 monitoring relay, so that the latter relay releases its armature for a short time. instant later, since it is of the delayed release type.



  By releasing its armature, the monitoring relay R 440 causes the de-energization of the signal output relay R 497 in the power line carrier 494 and, consequently, a new energization of the signal input relay R 395 in the carrier current equipment 394 and a resulting de-energization of the signal input relay R 350 in the junction circuit 200, all in the manner described above. By releasing its armature, the signal input relay R 350 causes the de-energization of the bonding relay R 340 a short time later, given that this last relay is of the delayed release type and the de-energization of the. R 240 battery reversal relay, all in the manner described above.

   By releasing its armature, the bonding relay R 340 interrupts, at contacts 341, the bonding circuit previously drawn which kept the time relay R 235 energized, so that the latter, when releasing its armature, interrupts at contacts 236, the circuit previously traced bonding relay which kept the R 380 bonding relay actuated. In this way, the latter relay releases its armature a short time later, since it is of the delayed release type. By releasing its armature, the bonding relay R 380 interrupts, at contacts 382, the bonding circuit previously drawn for the excitation of the lower winding of the relay in series R 250, in such a way that the latter relay releases its armature.



     At this moment, the communication established between the station of the calling subscriber T II of the remote exchange 10 and the called operator board 765 of the main office 40 is interrupted and all the devices interested in said communication are interrupted.

  <Desc / Clms Page number 68>

 completely released and become available for future use.



   From the foregoing, it will be understood that a communication can be established between a requesting prepaid station such as, for example, the T 12 prepaid station of the remote exchange 10, and the requested operator board 765 of the main office 40. in a substantially identical manner. However, it will be observed in this case that, when the selector of the researcher-selector junction used, such as, for example, the researcher-selector junction 203, operates, it is sensitive to the first digit "0" formed on the dial of the station. with prepayment requesting T 12 and selects a free junction in the bundle comprising in particular junction 220, for example, precisely said junction 220 which ends at junction circuit 200, an additional operation takes place.

   More precisely, given that the call considered at its origin at the prepayment station T 12 of the remote exchange 10, a tone potential is applied from the line circuit 214 associated with the line 212 via the finder junction -Selector 203 to the control conductor C 223 of the junction 220, so that the upper winding of the tone relay R 390 is excited by a tone current in the case considered. the tone current flowing through the upper winding of the tone relay R 390 causes the induction of a corresponding tone voltage in the lower winding of said relay. This induction is however meaningful effect at this time.



   Subsequently, when the operator of the switchboard 765 answers the call on the junction circuit 700 by inserting the front plug P 748 of the dicord 766 into the J 730 jack which terminates the junction circuit 700, assuming that the 'indicated apparatus is used in the considered communication, said apparatus operates in the manner explained above, so that the time relay R 280 of the junction circuit 200 operates

  <Desc / Clms Page number 69>

 first and then a short time later, the time relay R 235 operates in its turn by producing the de-energization of the time relay R 280, as explained previously.

   During the time interval in which the time relay R 280 occupies its energizing position, as indicated above, the lower winding of the tone relay R 390 is branched off on the line conductors C 301 and C 302 terminating at powerline carrier 394, so that the indicated acoustic tone is transmitted over line conductors C 301 and C 302 to carrier current apparatus 394. A short instant later, when the time relay R 280 releases its armature as indicated above, the transmission of the tone current on the line conductors C 301 and a 302 to the powerline carrier 394 is terminated.

   As a result, a tone "cue" is transmitted from trunk circuit 200 over line conductors C 301 and C 302 to powerline carrier 394 for a short period of time. identifies the prepaid post T 12 of the remote exchange 10 indicating to the operator 765 of the main office 40 the nature of said post.



   More precisely, the acoustic signal transmitted to the carrier current apparatus 394 produces a balanced modulator operation of said apparatus, so that the carrier signal at 24.55 kilocycles is modulated followed the tone signal and is transmitted by line 60 to power line carrier 494.

   Powerline carrier equipment 494 responds to the modulated 24.55 kilocycles carrier signal by transmitting the acoustic tone component of said signal over the previously traced connection comprising line conductors C 401 and C 402, junction 435, selector switch. arrival 429, junction 515, translator RC 650 of the junction circuit 500 of the tandem exchange 20, the junction line 665 connecting the exchange to the tandem 20, to the repeater ± ± ± the translator RC 675 'of the junction circuit 600 from repeater

  <Desc / Clms Page number 70>

 30 and line conductors C 601 and C 602 to powerline carrier equipment 694.

   More precisely, the acoustic signal transmitted to the power line carrier 695 produces the operation of the balanced modulator of said apparatus, so that the carrier signal at 24.55 kilocycles is modulated according to the tone signal and is transmitted over the line. 70 to the carrier current apparatus 794. The carrier current apparatus 794 responds to the modulated 24.55 kilocycles carrier signal by transmitting the tone component of said signal, through the connection above. traced including line conductors C 701 and C 702, at headset 767, operator panel 765 at main office 40.



   Said tone signal indicates to the operator at switchboard 765 at main office 40 that the call she is answering originated at a prepaid station at remote exchange 10, which reminds the operator at switchboard 765 that it must ask the person wishing to use the requesting prepaid set: 12 of the remote exchange 10 to insert the corresponding coin or token into said device after routing the call to the desired destination .

   Of course, it will be understood that if the tokens are subsequently deposited in the prepayment station T 12 of the remote exchange 10, this apparatus operates in such a way as to transmit identification tones, via the established connection of in a manner identical to that described above, at the operator switchboard 765 in main office 40.



   ATTEMPTED CALL WITHOUT TAX BETWEEN A SUBSCRIBER'S POSITION OR
A POST WITH PREPAYMENT FROM THE REMOTE CENTRAL 10 AND ONE
SUBSCRIBER STATION OR A PREPAYMENT STATION FROM THE TANDEM CENTRAL 20
In automatic telephony systems in which untaxed calls are authorized to switchboards

  <Desc / Clms Page number 71>

 operators, subscribers or others may accidentally learn that it is possible to route an untaxed or uncounted call to automatic switching devices at a distant point normally reached by a channel subject to counting via automatic switching devices.

   This prohibited routing of a communication is, in general, carried out by a subscriber or by another person who forms on his call dial the first digit designated as the call number of the operator switch panel followed by the digits composing the call number of the desired subscriber set or prepaid set at the remote point.

   For example, in the present system, a communication between a calling subscriber station T II, etc. or a prepaid calling station T 12, etc., of the remote exchange 10 can be routed to a called subscriber set T 21 etc ... or to a prepaid set T 22, etc ... of the tandem exchange 20, via a routing channel subject to metering passing through automatic switching devices, by forming on the call dial the indicative number "9" followed by the call number of the subscriber set or the requested prepaid set indicated.



  On the other hand, a call originating in a calling subscriber station T II etc ... or in a prepaid calling station T 12 etc ... of the remote exchange 10 can be routed to the switchboard. operator 765 of the main office 40 via a channel not subject to counting, passing through the automatic switching devices if the two digits "0" and "0" designated as number are formed on the call dial main office switchboard 765 call center 40.

   To attempt to initiate a prohibited call not subject to metering, the subscriber of the calling subscriber set T II, etc ... or of the requesting prepaid set T 12, etc ... of the remote exchange 10 can dial on his dial the indicative number "0"

  <Desc / Clms Page number 72>

 followed by the call number of a subscriber set or of a desired prepaid set from the tandem exchange 20. This combination of digits would achieve the desired goal if it were not provided for. 'avoid an improved interdiction device in junction circuits 200 etc ..., this device being described later in a more detailed form.



   It will first be assumed that a call has been made to the calling subscriber station T II of the remote exchange 10, that the searcher of the searcher-selector junction 203 has attacked the subscriber line 211 terminating at the subscriber station. calling party T II and that the subscriber of the calling subscriber station T II tends to establish a prohibited communication not subject to counting with the called subscriber station T 21 of the tandem exchange 20 by dialing on his call dial the indicative figure "0" followed by the call number "121" of the called subscriber set T 21 of the tandem exchange 20. the selector of the searcher junction selector 203 responds to the preliminary figure "0" by selecting the junction bundle comprising in particular the junction 220 then, in said bundle,

   a free junction. For example, the selector of the finder-selector junction 203 may select the particular junction 220 leading to the junction circuit 200. The devices of the junction circuit 200 are then controlled in such a way as to cause the operation of the powerline switchgear. 394 and powerline switchgear 494 and hence the operation of junction circuit 400, such that it drives inbound selector 429 of tandem exchange 20, all in the manner set forth. previously.

   However, in order to reach the requested subscriber station T 21 of the tandem exchange 20, it is necessary for the train of switches of said exchange including in particular the arrival selector 429 to receive the three digits "1", "2" and "1". "formed on the dial of the calling subscriber station T II of the remote exchange 10 after the attack of the junction circuit 200 via the junction 220 by the selector of the

  <Desc / Clms Page number 73>

 finder selector junction 203.



   Consequently, the subscriber of the calling subscriber station T II of the remote exchange 10 then proceeds to the formation on his call dial of the three digits "1", "2" and "I" composing the call number of the called subscriber station T 21 of the tandem exchange 20.



  Line relay R 330 operates according to the first and second digits "1" and "2" of the call number indicated by retransmitting the pulses of said digits, to contacts 333, to the signal output relay R 397 of the switchgear to Powerline carrier 394 so that the two digits shown are retransmitted by carrier current device 394, on line 60 to carrier power device 494, so that the signal input relay R 495 of the Powerline carrier equipment 494 retransmits the pulses of the two digits indicated to the contacts 496 to the signal input relay R 450 of the junction circuit 400 and the signal input relay R 450 of the junction circuit 400 retransmits, to contacts 451, the pulses of the two digits indicated on junction 435,

     all in the manner explained above. The arrival selector 429, in response to the number "1" indicated, selects the corresponding junction bundle comprising in particular the junction 428 then, in this fa. seal, a free junction. For example, the arrival selector 429 may elect the particular junction 428 which terminates at the city connector 427.

   The urban connector 427, in response to the number "2" indicated, then selects the corresponding group of subscriber lines comprising in particular the subscriber line 421. However, at this moment, and before the operation of the urban connector 427 having the effect to select the subscriber line 421 which terminates at the called subscriber station T 21 of the tandem exchange 20, the trunk circuit 200 of the remote exchange 10 operates by blocking the communies. tion and preventing the final operation of the urban connector 427 of the tandem exchange 20, 'as indicated above.

  <Desc / Clms Page number 74>

 



   More precisely, in the junction circuit 200, when the line relay R 330 responds to the first digit "I" indicated, the operation and subsequent de-energization of the numbering relay R 320 is carried out in the manner explained previously.



  While operating, the numbering relay R 320 closes, at contacts 325, the circuit previously drawn for the parallel excitation of the upper and lower windings of the numbering relay R 370, so that the latter relay performs the first phase of its operation. staggered by closing, at contacts 375, the circuit previously drawn for short-circuiting the upper winding of said relay. By releasing its armature, the numbering relay R 320 interrupts, at contacts 325, the circuit previously drawn for the short-circuiting of the upper winding of the numbering relay R 370, so that the latter relay performs the second phase of its phased operation.



   When the line relay R 330 then responds to the second indicated digit "2", the operation and then release of the numbering relay R 320 takes place as before. When operating again, the number relay closes, at contacts 325, a circuit through contacts 382, 245, 254, 363 and 374 for energizing the upper winding of the number relay R 360 and a substantially identical circuit. also passing through contacts 376 and 367 and through resistor 345 for the excitation of the lower winding of the number R 360 relay, so that the latter relay performs the first phase of its staggered operation by closing, at contacts 366, a circuit passing through contacts 325, 363 and 374 and ensuring the short-circuiting of the lower winding of said relay.

   By releasing its armature, the numbering relay R 320 then interrupts, at contacts 325, the circuit previously drawn for the short-circuiting of the lower winding of the numbering relay R 360, so that the latter relay performs

  <Desc / Clms Page number 75>

 the second phase of its staggered operation as a result of the excitation of the upper and lower windings of said relay in series by a circuit passing through contacts 366, 254, 245 and 382.

   Carrying out the second phase of its staggered operation, the number relay R 360 closes, at contacts 368, a direct circuit for the application of an earth potential to the signal output conductor C 303, which absolutely prevents the operation of the line relay R 330 and the retransmission, to contacts 333, of the third digit "I" indicated on the signal output conductor C 303.



   On the other hand, the number relay R 360 interrupts, at contacts 365, the original circuit passing through contacts 375, 254, 245 and 382 for the series excitation of the upper and lower windings of the number relay R 370 and closes , at contacts 364, a variant circuit passing through the contacts
245 375, 326, 254 and 382 for the series excitation of the upper and lower windings of the number relay R 370.

   In addition, at this moment, the actuated digit relay R 360, interrupts, at contacts 362, an original loop circuit point previously drawn for the series excitation of the upper and lower windings of the line relay R 330 and closes, at the contacts 361, a point of an additional circuit also passing through the contacts 371 and included in the loop circuit for the series excitation of the upper and lower windings of the line relay R 330.



   Consequently, when the subscriber of the calling subscriber station T II of the remote exchange 10 forms the indicated third digit "I" on his dial, the line relay R 330 operates correspondingly by causing the dial relay to be energized again. R 320 as explained above. the line relay R 330 activates the contacts 333 according to the single impulse of the figure "I" considered, this operation has no effect since the number relay R 360 constantly maintains

  <Desc / Clms Page number 76>

 an earth potential at contacts 368 on the C signal output conductor 303, so that powerline carrier equipment 394 does not receive the indicated third digit "1".



  At this moment, attracting its armature again, the numbering relay R 320 interrupts, at contacts 326, the variant circuit previously drawn for the series excitation of the upper and lower windings of the number relay R 370, from so that this last relay releases its armature.

   By releasing its arnature, the number relay R 370 interrupts, at contacts 371, the additional point of the loop circuit previously drawn for the series excitation of the upper and lower windings of the line relay R 330 and closes, at contacts 372, another circuit passing through the contacts 361 for the series excitation of the upper and lower windings of the line relay R 330 via a loop circuit terminating at the requesting subscriber stations T II and also comprising the winding secondary of busy tone transformer 346.

   In con. sequence, the busy tone current or the forbidden tone current crosses the last indicated loop circuit and returns to the calling subscriber station T II of the remote exchange 10, indicating to the subscriber of said station the busy condition artificial or the unauthorized dialing combination, depending on whether one or the other of the two tones indicated above is used.

   Since the subscriber of the calling subscriber station T II of the remote exchange 10 cannot control the final operation of the city connector 427, so that the latter attacks the subscriber line 421 terminating at the station. calling subscriber T 21 of the tandem exchange 20, any extension of the call beyond this point is effectively prohibited in the junction circuit 200.

   Subsequently, when the subscriber of the subscriber station T II of the remote exchange 10 hangs up, the city connector 427, the arrival selector 429, the trunk circuit 400 and the power line apparatus 494 of the central exchange. in

  <Desc / Clms Page number 77>

 tandem 20, as well as powerline carrier equipment 394, junction circuit 200 and searcher-selector junction 203 of remote exchange 10 are released in the manner previously discussed.



   From the foregoing, it will be understood that, since the communication described above has been blocked as a result of the function on the call dial of the two digits following the attack of the trunk circuit 200 by the station d The calling subscriber T II, an identical operation takes place in the event that an unauthorized call of the same type is attempted in a T 12 prepayment set, etc ... of the remote exchange 10.



   PPO CALL FROM THE OPERATOR'S SWITCH PANEL
FROM MAIN OFFICE 40 AND FOR A SUBSCRIBER POSITION
OR TO A: POST WITH PREPAYMENT OF THE REMOTE CENTRAL 10.



   Assume first that the attendant at main office 40 attendant switch panel 765 has answered a call using the T 758 back plug of dicorde 766 which requires routing to a called subscriber station. such as, for example, the subscriber station T II of the remote exchange 10. The operator inserts the front plug P 748 of the dicorde 766 into a jack terminating a free junction circuit of the bundle comprising in particular the junction circuit 700 .

   Assuming that the junction circuit 700 is free at this moment, as indicated by the extinction condition of the busy lanpe L 732, the operator of the switchboard 765 can insert the front plug P 748 into the J 730 jack which terminates the junction circuit 700 after placing the dial key K 737 of the dicorde 766 in its position had. when the front plug P 748 is thus inserted into the jack J 730, the contacts 731 of said jack are closed, which completes an obvious circuit for the energization of the jack relay, R 710 in the junction circuit 700. In operation, the jack relay R 710 closes, at contacts 713, an obvious circuit for switching on the occupancy lamp L 732, so as to

  <Desc / Clms Page number 78>

 indicating that the junction circuit 700 is busy at this time.



  On the other hand, when the front plug P 748 is inserted into the J 730 jack, the respective plug bodies of these two members come into contact and close a circuit passing through the contacts 741 for the energization of the relay winding. front monitoring R 745 in dichord 766 in series with the lower winding of the plug relay R 720 in the junction circuit 700 and a multiple circuit also passing through contacts 712 and 706 for energizing the winding top of the plug relay R 720 in parallel with its lower winding. As a result, the plug relay R 720 of the junction circuit 700 operates and the forward monitoring relay R 745 of the dicorde 766 also operates, since it is of the marginal type.



  When operating, the front monitoring relay R 745 closes, at contacts 746, an obvious circuit for switching on the front monitoring lamp L 747, so as to indicate that the call in question has not yet been sent and has not yet been answered. On the other hand, when operating, the jack relay R 710 interrupts, at contacts 715, the circuit previously drawn for the short-circuiting of the upper winding of the signal input relay R 705, so as to give to the latter relay fast attractive characteristics when its lower winding is subsequently energized.



   In addition, while operating, the plug relay R 720 establishes, at contacts 723 and 726, a clear connection between the line conductors C 701 and C 702 terminating at the powerline carrier 794 and the tip and tip wires. loop of jack J 730 and, therefore, the tip and loop of the front plug P 748 of dicorde 766. At this time, the pulse contacts 762 of the call dial D 760 incorporated in dicorde 766 are set. derivation by coitus acts of working of the dialing key K 737, the contacts of the calling key

  <Desc / Clms Page number 79>

   X 736 idle and the idle contacts of the front conversation key X 734 on the tip and loop of the front plug P 748.



  On the other hand, while operating, the plug relay R 720 closes, at the contacts 721, a circuit passing through the contacts 711 for the application of a battery potential via the resistor 709 to the output conductor of C 703 signals so as to close an obvious circuit for energizing the R 797 signal output relay in powerline carrier equipment 794, When operating, the R 797 signal output relay closes the 798 contacts included in the circuit transmission amplifier anode, so that the 15.95 kilocycle carrier signal is transmitted through carrier current equipment 794, line 70 connecting main office 40 to repeater 30.

   The carrier current apparatus 694 of the repeater 30 responds to the 15.95 kilocycles carrier signal transmitted to it through line 70 so as to de-energize the signal input relay R 695.



  This last relay interrupts, at contacts 696, the circuit previously indicated for the application of a battery potential to the signal input conductor C 604, so as to cause de-energization of the signal input relay R 670 in the junction circuit 600,
By releasing its armature, the signal input relay R 670 interrupts, at contacts 671, the normally closed circuit previously drawn which kept the attack relay R 585 energized in the junction circuit 500 to the tandem exchange 20.



  By releasing its armature, the attack relay R 585 closes, at contacts 586, a circuit passing through the contacts 622 for the excitation of the upper winding of the control relay R 590 in such a way that the latter relay is energized. . When operating, the control relay R 590 closes, at contacts 594, a circuit passing through contacts 622 for energizing the monitoring relay R 560. When operating, the monitoring relay R 560 closes, at contacts 562, a circuit passing

  <Desc / Clms Page number 80>

 by contacts 572 for energizing the lower winding of switching relay R 630, in such a way that the latter attracts its armature.

   While operating, the switching relay R 630 closes, at contacts 631, 633, 635, 636 a loop circuit between the right winding of the response relay R 595 and the line conductors C 521 and C 522 of junction 520 terminating at the arrival selector 434 and interrupts, at contacts 632 and 634, the normal connections between the upper and lower windings of the line relay R 610 and the line conductors C 511 and C 512 of the junction 510.

   The loop circuit shown above starts from line conductor C 521 of junction 520, passes through contacts 631 and 642, winding 651 of translator RC 650, contacts 633, right winding of relay response R 595, contacts 635, winding 652 of the RC 650 trans- lator, contacts 636, 621, and 591, to end in line conductor C 522 of junction 520. When this loop circuit is thus closed, the right-hand winding of the R 595 response relay is energized.

   However, this last relay is not polarized at this moment, so that it is actuated, On the other hand, the arrival selector 434 is driven and operates in such a way as to return a ground potential to the control conductor C 523 of junction 520, which closes an obvious circuit for energizing the left winding of the response relay R 595 and a multiple bonding circuit for energizing, - tion of the upper winding of the relay switch R 630.



  In addition, when operating, the control relay R 590 closes, at contacts 593 a circuit passing through contacts 613 and 582 for the application of a battery potential through the upper winding of the pulse relay R 620 at the simplex between windings 653 and 654 of the RC 650 translator, however the lower and middle windings of the R 660 signal output relay of the junction circuit 600 are not energized at this time by the junction line 665 due to function

  <Desc / Clms Page number 81>

 blocking of the copper oxide rectifier 667 with respect to the current in the indicated direction, so that the pulse relay R 620 of the junction circuit 500 and the signal output relay R 660 of the junction circuit 600 remain in their rest position.

   At this time, inbound selector 434 has been engaged and is conditioned to be responsive to the first digit which is to be formed on the call dial of the calling operator switch board 765. main office 40.



   The operator of the operator switch panel 765 of the main office 40 then proceeds to the formation on her call dial of the number "0" which indicates that the communication in question must be routed to the remote exchange 10, then the number of call from the called subscriber station T 11 of said exchange, call number which may for example be "III". Thus the number "0" III "is formed on the call dial of operator switchboard 765 in main office 40.

   When the call dial D 760 numbering disc included in dichord 766 is rotated out of its rest position, the shunt contact set 761 is closed and remained closed until said disc was returned to its original position. rest position while the pulse contact spring set 762 is actuated so as to transmit the pulses of the digit under consideration only during the return of the take-up disc to its rest position. -When the D 760 call dial disc is rotated out of its rest position by closing the shunt contact set 761, a circuit passing through the working contacts of the X 737 dial key is closed for the 'energization of the front dial relay R 740.

   When operating, the front numbering relay R 740 interrupts, at contacts' 741, the circuit previously drawn for the energization of the winding of the monitoring relay.

  <Desc / Clms Page number 82>

 front R 745 in series with the multiple connecting the upper and lower windings of the plug relay R 720, so that the indicated relays release their armature.

   By releasing its armature, the front monitoring relay R 745 at dicorde 766 interrupts, at contacts 746, the circuit previously drawn for the ignition of the front monitoring lamp L 747 and, by releasing its armature, the relay of plug R 720 of the junction circuit 700 interrupts, at contacts 723 and 726, the connection previously established between the line conductors C 701 and C 702 leading to the powerline carrier equipment 794 and the tip and the loop of the jack J 730 .

   On the other hand, the plug relay R 720 reforms, at contacts 725, the previously indicated terminating circuit comprising the resistor 717 at the terminals of the line conductors C 701 and C 702 and interrupts, at contacts T 21, the Original circuit previously drawn for the application of a battery potential, via resistor 709, to the C signal output conductor 703.

   Finally, the plug relay R 720 closes, at contacts 724 and 727, a variant circuit passing through contacts 7II, the jack J 730, the front plug P 748, and the pulse contacts 762 of the call dial D 760 incorporated in dichord 766 for the application of a battery potential, via resistor 718, to the signal output conductor C 703, which keeps the signal output relay R 797 actuated in powerline carrier equipment 794.

   However, since the circuit traced above for energizing the winding of the R 797 signal output relay in the power line carrier 794 goes through the pulse contacts 762 of the call dial D 760 incorporated in dichord 766, the digit impulses considered trans-

  <Desc / Clms Page number 83>

 initiated by the pulse contacts 762 of the call dial D 760 as a result of the return to the rest position of the dial disk of said call dial are transmitted by the signal output conductor C 703 of the output relay of signals R 797 from powerline carrier equipment 794, so that the latter relay operates correspondingly and the signal output relay R 797 transmits, to contacts 798, the pulses of the lower digit on line 70.

   More precisely, the carrier current equipment 794 interrupts the carrier signal at 15.95 kilo- cycles following the pulses of the digit concerned, so that the signal input relay R 695 of the carrier current apparatus 694 transmits corresponding imputations of battery potential to the contacts 696 on the signal input conductor C 604, which causes a corresponding operation of the signal input relay R 670 in the junction circuit 600 .



   The numbering disc of the call dial D 760 incorporated in the dicorde 766 is first actuated according to the indicative number "0", as indicated above and when said disc returns to its rest position, the contacts of pulses 762 of the call dial D 760 have terminated the transmission of the pulses of the indicated digit and the shunt contacts 761 of the call dial D 760 are opened by interrupting the circuit previously drawn which kept the dial relay energized before R 740 so that the latter releases its reinforcement a short time later since it is of the delayed release type.

   By releasing its armature, the front numbering relay R 740 closes, at contacts 741, the circuit previously drawn for the excitation of the front monitoring relay R 745 in the dicorde 766 and of the plug relay R 720 in the junction circuit 700. When operating again, the front monitoring relay R 745 lights up at

  <Desc / Clms Page number 84>

 again the front monitoring lamp L 747 and, when operating again, the plug relay R 720 closes, at contacts 721, the original circuit previously drawn for the application of a battery potential by means of the resistance 700 to the signal output conductor C 703,

   this keeps the signal output relay R 797 in the power line carrier 794 actuated and maintains the signal input relay R 695 in the power line carrier 694 and the input relay in the rest position of signals R 670 in the junction circuit 600, as explained previously.

   On the other hand, when operating again, the plug relay R 720 interrupts, at contacts 725, the termination circuit passing through resistor 717 in shunt on line conductors C 701 and C 702 leading to the current switchgear. carrier 794, interrupts at contacts 724 and 727, the variant circuit passing through pulse contacts 762 of call dial D 760 incorporated in dicorde 766 for the application of a battery potential via of the resistor 718 to the signal output conductor C 703 and closes, at the contacts 723 and 726, the connection previously established between the line conductors C 701 and C 702 and the dichord 7660 'From the above, it will be understood that the call dial D 760 incorporated in the dicorde 766 is actuated successively according to the digits "0",

   "1", "1", and "I", so that the four digits shown are transmitted from the call dial D 760 to the signal output relay R 797 of the powerline carrier equipment 794 and retransmitted on line 70 to signal input relay R 695 of powerline carrier 694, then retransmitted to signal input relay R 670 in junction circuit 600.

   In addition, at the end of the numbering process, the operator at switchboard 765 in main office 40

  <Desc / Clms Page number 85>

 activates the front conversation key K 734 so as to establish the previously indicated connection between the helmet 767 of said board and the tip and the edge of the front plug P 748 of the dicorde 766, and, of the, 'with the line conductors C 701 and C 702 resulting in the current carrier equipment 794. In addition, at this time, the numbering key K 737 of the dicorde 766 is returned to its rest position since all digits have been transmitted. .



   The signal input relay R 670 of the junction circuit 600 by operating according to the indicative number "0" as indicated above, attracting and releasing its armature according to the pulses of said circuit. Each time the signal input relay R 670 attracts its armature and then releases it, it closes then interrupts, at contacts 671, a circuit passing through contacts 661 and through the copper oxide rectifier 666 for the 'application of an earth potential to the simplex between the windings 676 and 677 of the translator RC 675, so that, the corresponding earth potential pulses are transmitted on the junction line 665, being that the rectifier at the copper oxide 666 allows current to flow in the direction indicated.

   The earth potential pulses transmitted to the contacts 671 of the signal input relay R 670 of the junction circuit 600, through the junction line 665, intermittently closes the circuit previously drawn for the excitation of the upper winding of the R 620 impulse relay of the junction circuit 500, so that the latter relay operates in a corresponding way attracting and releasing its armature according to the pulses of the figures indicated.

   Each time the R 620 pulse relay attracts then releases its armature, it interrupts, then closes, at contacts 622, the multiple circuits previously traced for the excitation of the upper winding of the R 590 control relay and of the wind-

  <Desc / Clms Page number 86>

 ment of the monitoring relay R p60. However, the indicated relays remain actuated during pulse transmission since they are of the delayed release type.

   On the other hand, each time the pulse relay R 620 attracts and then releases its armature, it closes then interrupts, at contacts 621 ', a circuit passing through contacts 563 for the energization of the numbering relay R 640. , so that the latter relay attracts its armature and remains actuated during the transmission of the impulses, since it is of the delayed release type. While operating, the numbering relay R 640 closes, at contacts 646, a bonding circuit for the energization of the lower winding of the control relay R 590, which effectively prevents the release of the armature. the latter relay during pulse transmission.

   In addition, while the numbering relay R 640 is in operation, it closes, at contacts 643, a circuit passing through resistor 618, winding 651 of translator RC 650, contacts 633 and resistor 619 for short-circuiting. of the right winding of the response relay R 595, which effectively prevents the operation of the latter relay during the transmission of the pulses and which reduces the impedence of the loop circuit leading to the arrival selector 434 on the junction 520.



   Finally, each time the R 620 pulse relay attracts then releases its armature, it interrupts and then closes, at contacts 621, the previously traced loop circuit comprising the line conductors C 521 and C 522 of junction 520 leading to the selector arrival 434, so that the pulses of the indicative digit "0" are retransmitted by the pulse relay R 620 to contacts 621 to the arrival selector 434. The arrival selector 434 responds to the digit "0" by selecting the bundle of junctions comprising in particular

  <Desc / Clms Page number 87>

 junction 430, then by selecting a free junction in said bundle.

   For example, arrival selector 434 may select the particular junction 430 terminating at junction circuit 400, with junction 430 being indicated as free at arrival selector 434 by the application of a battery potential to the control lead. C 433 via a circuit passing through contacts 483 and 466 and through impedance 458. When the arrival selector 434 drives junction 430, a loop circuit is closed for the excitation in series of the upper and lower windings of the line relay R 470 in the junction circuit 400.

   the indicated loop circuit goes through the contacts 402 and 404 and includes the line conductors C 431 and C 432 of the junction 430, so that the line relay R 470 works, Accordingly, the loop circuit indicated above is at this moment closed between the right winding of the response relay R 595 of the junction circuit 500 and the upper and lower windings of the line relay R 470 of the junction circuit 400.



   While operating, the line relay R 470 of the junction circuit 400 interrupts, at contacts 471, the termination circuit previously drawn comprising the capacitor 443 and the resistor 444 in shunt on the line conductors C 401 and C 402 leading to the current carrier 494 and closes, at contacts 472, an obvious circuit for energizing the R 480 bonding relay.

   While operating, the bonding relay R 480 interrupts, at contacts n483, the original circuit previously drawn for the application of a battery potential via the impedence 458 to the control conductor C 433 of the junction 430 and closes , at contacts 484, a circuit for applying an earth potential via the winding of the control relay R 490 to the conductor

  <Desc / Clms Page number 88>

 control relay C 433, which causes the operation of the control relay R 490.

   When the battery potential which was applied to the control conductor C 433 of junction 430 is replaced by a ground potential, the junction 430 is indicated as being occupied at the other arrival selectors of the group including the arrival selector 434 and to the selectors of the seeker-selector junctions 426 etc ... which have access to said junction. Finally, while operating, the line relay, R 470, closes an obvious circuit at contacts 473. for the application of an earth potential to the signal output conductor C 403, so as to trigger the operation of the signal output relay R 497 in the carrier current device 494.



   When operating, the signal output relay R 497 triggers the operation of the carrier current switchgear 494, so as to ensure the transmission of the carrier signal at 15.95 kilocycles on line 60, which connects the tandem exchange 20 to the remote central 10, which causes the armature of the signal input relay, R 395 in the carrier switchgear 394 to be released and a ground potential applied to contacts 396 at the C 304 signal input conductor so that the R 350 signal input relay of the junction circuit 200 is energized.



  When operating, the signal input relay R 350 closes, at contacts 352, an obvious circuit for energizing the R 340 bonding relay. When operating, the R 340 bonding relay closes, at contacts 342, a circuit passing through contacts 386 for energizing the lower winding of switching relay R 260 in such a way that the latter relay attracts its armature.

   When operating, the switching relay R 260 interrupts, at contacts 266, the circuit previously drawn for the application of a potential

  <Desc / Clms Page number 89>

 battery via the impedance 257 to the control conductor C 223 of the junctions 220 and 225 and closes, at the contacts 267, a circuit passing through the contacts 383 for the application of a ground potential to the conductor control C 223, which indicates that the junctions in question are assigned to the selector switches of the seeker-selector junctions 203, etc ... In addition, the switching relay R 260 interrupts at contacts 261 and 264,

   the connection previously drawn between the line conductors C 221 and C 222 of the junction 220 and the line conductors C 301 and C 302 leading to the powerline carrier 394 and closes, at the contacts 263, a circuit passing through the contacts 351 which bypasses the left winding of the response relay @ 310 on the line conductors C 231 and C 232 of the junction 230 leading to the arrival selector 206, so that the left winding of the relay response R 310 is energized on the loop circuit starting from said relay, passing through junction 230 and ending at arrival selector 206, but said relay is not polarized at this time in such a way that it can operate.

   However, the arrival selector 206 is driven and made responsive to a digit passed back to said selector by the indicated loop circuit and on the other hand operates to return a potential to earth on the control conductor C 233 of junction 230. , which closes a circuit for the energization of the right winding of the response relay R 310 and a multiple bonding circuit for the energization of the upper winding of the switching relay R 260.



   When the signal input relay R 670 of the junction circuit 600 then receives the first digit "I" of the call number of the called subscriber station T II of the remote exchange 10, it retransmits the pulse from this digit at contacts 671 to pulse relay 620 of the junction circuit

  <Desc / Clms Page number 90>

 500, as explained previously, The pulse relay R 620 operates according to the figure "1" indicated by retransmitting, to the cont acts 621, the pulse of said figure by the loop circuit comprising the junction 520, the arrival selector 434 and the junction 430 to the line relay R 470 of the junction circuit 400, so that the latter relay operates according to said pulse.

   Line relay R 470 and junction circuit 400 retransmitting, to contacts 473, the pulse of the number "1" indicated to signal output relay R 497 of powerline carrier 494, so that the latter relay retransmits said pulse to its contacts 498 and that the carrier current apparatus 494 retransmits it on line 60 to the carrier current apparatus 394; the signal input relay R 395 then operates accordingly. The signal input relay R 395 of the powerline carrier switchgear 394 transmits the pulse of the number "1" indicated on the signal input conductor C 304 to its contacts 396 to the input relay of R 350 signals of junction circuit 200.

   Each time the signal input relay R 350 of the junction circuit 200 releases its armature and then attracts it again, it interrupts and then closes, at contacts 352, the circuit which keeps the sticking relay R 340 actuated. However, the latter relay remains actuated during the transmission of the pulses since it is of the delayed release type. In addition, each time the signal input relay R 350 releases its armature and then attracts it again, it closes and then interrupts at contacts 353, a circuit passing through contacts 343 for energizing the relay winding. numbering R 320 so that the latter relay energizes and remains actuated during the transmission of the pulses, since it is of the delayed release type.

   While operating, the numbering relay R 320 closes, at contacts 322, a

  <Desc / Clms Page number 91>

 circuit passing through resistor 327 for short-circuiting the left winding of the response relay R 310, which effectively prevents the operation of the last relay during the transmission of the pulses and which reduces the impedance of the circuit loop terminating via junction 230 at arrival selector 206, Finally, each time the signal input relay R 350 releases its armature, then attracts it again, it interrupts then closes again, at the contacts 351, the previously traced loop circuit terminating, via junction 230, at arrival selector 206,

   so that the arrival selector 206 operates according to the number "1" considered by selecting the bundle of junctions comprising in particular the junction 207 then, in this bundle, a free junction. For example, arrival selector 206 may select the particular junction 207 terminating at city connector 205, which extends the loop circuit from the left winding of response relay R 310 of junction circuit 200 through the junction 230, the arrival selector 206 and the junction 207 to the city connector 205, so that the city connector 205 is packaged in such a way that it is sensitive to the next two digits that it receives.



     At the end of the transmission of the code number "0", the signal input relay R 670 of the junction circuit 600 remains in the rest position, which causes the return to the same position of the relay. pulses R 620 of the junction circuit 500, so that the numbering relay R 640 releases its armature a short instant later by interrupting, at contacts 643, the circuit previously drawn including resistor 618 and putting in short circuit the right-hand winding of the R 595 response relay.



  On the other hand, the line relay R 470 of the junction circuit

  <Desc / Clms Page number 92>

 400 remains actuates stably and keeps the bonding relay R 480 and the signal output relay R 497 of the powerline carrier switchgear 494 actuated, so that the signal input relay R 395 of the switchgear to carrier current 394 is maintained in its rest position causing stable operation of the signal input relay R 350 in the junction circuit 200. The actuated signal input relay R 350 interrupts, at contacts 353, the previously circuit. trace which kept the numbering relay R 320 energized, in such a way that the latter releases its armature a short time later since it is of the delayed release type.

   By releasing its armature, the numbering roller R 320 interrupts, at contacts 322, the previously drawn circuit comprising the resistor 327 which short-circuited the left winding of the response relay R 310.



   Similarly, the signal input relay R 670 retransmits the second digit "I" and the third digit "I" of the call number of the called subscriber station T II of the remote exchange 10 to the contacts. 671, so that the pulse relay R 620 of the junction circuit 500 works - according to the two digits indicated by retransmitting them, at the contacts 621, to the line relay R 470 of the junction circuit 400.

   the line relay R 470 of the junction circuit 400 retransmits the two digits indicated at contacts 473 to the signal output relay R 497 of the power line carrier 494 so that the latter relay retransmits the two digits indicated at contacts 498 on line 60, which causes corresponding operation of signal input relay R 395 of powerline carrier switchgear 394.

   The signal input relay R 395 retransmits the two digits indicated at contacts 396 to the signal input relay R 350 of the junction circuit 200 and the latter relay

  <Desc / Clms Page number 93>

 retransmits said digits to contacts 351, via junction 230, arrival selector 206 and junction 207 to urban connector 205. Urban connector 205 in response to two digits "1" and " 1 "selects the subscriber line 2II which terminates at the called subscriber station T II of the remote exchange 10. The subsequent operation of the urban connector 205 depends on the occupation or non-occupation condition of the called subscriber station T 11 at the moment considered.



   It will first of all be assumed that the requested subscriber station T 11 is busy at this time. The urban connector 205 then returns a busy tone current on the junction 207 and the arrival selector 206 to the line conductors C 231 and C 232 of the junction 230.

   At this time, the line conductors C 231 and C 232 of the junction 230 are connected through the contacts 263, 321 and 262 and the capacitor 347 and through the contacts 351 and 265 and the capacitor 348 to the conductors line C 301 and C 302 which terminate in carrier current equipment 394, so that carrier current equipment 394 transmits the carrier signal at 24.55 kilocycles modulated by the busy signal at acoustic frequency on the line 60 so that the carrier current equipment 494 responds to the carrier signal at 24.55 kilocycles by transmitting its acoustic component on the line conductors C 401 and C 402.



  Line conductors C 401 and C 402 are connected through contacts 461, 464, and 402, 404 to conductors C 431 and C 432 of junction 430 and through the arrival selector. 434, to the line conductors C 521 and C 522 of junction 520.

   Line conductor C 521 of junction 520 is connected via contacts 631, 642 of winding 651, translator RO 650, capacitor 655, winding 652, translator RC 650 and contacts 636, 621, and 591, to the conductor

  <Desc / Clms Page number 94>

 line C 522, from junction 520, so that the busy tone current flowing through the coils 651 and 652 of the RC 650 translator induces a corresponding busy tone current in the coils 653 and 654 of said translator, which current is transmitted through the line conductors of the junction line 665 to the windings 676 and 677 of the RC 675 translator.

   the busy tone current flowing through the windings 676 and 677 of the RC 675 translator induces a busy tone current in the windings 678 and 679 of said translator and this current is transmitted through the line conductors C 601 and C 602 to the load-bearing covrant switchgear 694.

   The carrier current apparatus 694 transmits the carrier signal at 24.55 kilocycles modulated by the busy signal at acoustic frequency on line 70, so that the carrier current apparatus 794 responds to the carrier signal at 24, 55 kilocycles Modulated by transmitting its acoustic component to the line conductors C 701 and C 702, the contacts 723 and 726, the jack J 730, the front plug P 748 and the contacts of the front conversation key K 734 activated from the dicorde 766 to the headset 767 of the operator switch panel 765, which indicates to the operator of said panel that the called subscriber station T II of the remote exchange 10 is busy at this time.



  The operator of the switchboard 765 then proceeds to release the apparatus by removing the front plug P 748 of the dichord 766 of the jack J 730 in a manner which will be explained later in a more detailed form.



   On the other hand, in the case where the requested subscriber station T II of the remote exchange 10 is free at this moment, the urban connector 205 applies a inrush current to the subscriber line 211 which terminates at said station and returns Calling party caller warning tone stream on junction 207 and the circuit previously drawn at the main office attendant switchboard 765

  <Desc / Clms Page number 95>

 cipal 40 in a manner substantially identical to that set forth above.

   Subsequently, when the subscriber of the called station T 11 of the remote exchange answers the call, the urban connector 205 reverses the polarity of the junction 207, and consequently of the arrival selector 206 and of the line conductors C 231 and C 232 of junction 230, so that the left winding of response relay R 30 of junction circuit 200 is biased so that it is actuated.

   On operation, the response relay R 310 interrupts, at contacts 311, the terminating circuit previously drawn comprising resistor 344 and capacitor 286 in shunt on the line conductors C 301 and C 302 which terminate at the switchgear 394, and closes, at contacts 312, an obvious circuit for energizing the upper winding of monitoring relay R 270 in such a way that the latter relay attracts its armature.



  During operation, the monitoring relay R 270 closes, at contacts 272, an obvious circuit for the application of an earth potential to the signal output conductor C 3C3 so as to cause the operation of the signal output relay R 397. in powerline carrier equipment 394 and consequently releasing the armature of signal input relay R 495 in carrier current equipment 494 in the manner previously discussed.



   By releasing its armature, the signal input relay R 495 closes, at contacts 496, the circuit previously drawn for the application of an earth potential to the signal input conductor C 404 so as to cause the operation of the signal input relay R 450 in the junction circuit 400, When operating, the signal input relay R 450 closes, at contacts 452, the circuit previously drawn for energizing the bonding relay R 400.

  <Desc / Clms Page number 96>

 



   When operating, the bonding relay R 400 reverses, at contacts 401, 402 and 403, 404, the polarity of the line conductors C 431 and C 432 of junction 430 with respect to the upper and lower windings of the line relay
R 470, so that the polarity of the line conductors
C 521 and C 522 of junction 520 is reversed with respect to ### ### at X at arrival selector 434 giving the right winding of response relay R 595 of the junction circuit
500 a polarity such that said relay can operate,
In operation, the response relay R 595 closes, at contacts 597, an obvious circuit for energizing the lower winding of the monitoring relay R. 580 in such a way that the latter relay attracts its armature.



   While operating, the R 580 monitoring relay closes, at contacts 584, an obvious bonding circuit for the energization of the lower winding of the R 590 control relay and interrupts, at contacts 582, the circuit previously drawn for the 'application of a battery potential via the upper winding of the R 620 pulse relay to the simplex between the windings 653 and 654 of the RC 650 translator.

   Finally, the R 580 monitoring relay closes, at contacts 581, a circuit passing through contacts 613 and 595 for the application of a positive potential from the overvoltage battery 616 by means of the '' lower winding of the pulse relay
R 620 at the simplex between windings 653 and 654 of the RC 650 trans- late, so that the lower and middle windings of the signal output relay R 660 of the junction circuit 600 are energized in series with the lower winding of the relay d 'R 620 pulses in the junction circuit 500, by the previously traced circuit comprising the copper oxide rectifier 667. When this series circuit is closed, the R 660 signal output relay

  <Desc / Clms Page number 97>

 of the junction circuit 600 operates.

   On the other hand, the pulse relay R 620 of the junction circuit 500 does not work since it is of the marginal type.



   While operating, the signal output relay R 660 of the junction circuit 600 closes, at contacts 663 the circuit previously drawn for the application of an earth potential to the signal output conductor C 603, so as to cause operating the R 697 signal output relay in power line carrier 694 and releasing the armature of the R 795 signal input relay in power line carrier 794 in the manner previously discussed.

   By releasing its armature, the signals input relay R 795 of the power line carrier equipment 794 closes, at the contacts 796, the circuit previously drawn for the application of an earth potential to the signal input conductor C 704 so as to energize the lower winding of the signal input relay R 705 in the junction circuit 700, so that the latter relay operates instantaneously at the time in question.

   When operating, the R 705 signal input relay interrupts at contacts 706; the circuit previously drawn for the excitation of the upper winding of the plug relay R 720 in the junction circuit 700 in series with the winding of the front monitoring relay R 745 in the dichord 766, so that only the winding lower part of the plug relay R 720 is energized in series with the winding of the front monitoring relay R 745. The plug relay R 720 is held in its operating position; on the other hand, the front monitoring relay R 745 releases its armature since it is of the marginal type.

   On the other hand, when operating, the signal input relay R 705 closes, at contacts 707, a multiple circuit for switching on the occupancy lamp L 732. when it is restored, the front monitoring relay R 745 opens, at contacts 746, the circuit indicated above

  <Desc / Clms Page number 98>

 to switch on the front monitoring lanpe L 747 in order to inform the operator on switchboard 765 at the main office 40 that the subscriber of the set called T 11 at the remote exchange 10 has answered the call.



   The subscriber of the calling operator set 765 can converse with the subscriber of the called T II set at the remote exchange 10. As a result, the modulated carrier signals and the audible signals travel through the various parts of the link completed in the manner indicated above. .

   At this moment, the operator of table 765 can restore the front conversation key K 734 to its normal position by completing a link between the subscriber station called T II of the remote exchange 10 and the original calling connection at which it is first responded to operator panel 765 using rear plug P 758 of dicorde 766 since this front plug. 748 is directly connected to the rear connector P 758 when the front conversation key Y 734 of the dicorde 766 is returned to its normal position.



   At the end of the established conversation, when the subscriber of the set called T II at the remote exchange hangs up, the local connector 205 operates to reverse the polarity of the junction 207, in order to introduce the left winding of the response relay R 310 in the junction circuit 200 with a view to its restoration.

   during this reestablishment, the response relay R 310 again completes, at contacts 3II, the terminating circuit indicated previously and comprising resistor 344 and capacitor 286, in parallel with the line conductors C 301 and C 302 terminating to carrier current equipment 394, and it interrupts, at contacts 312, the circuit previously drawn for the excitation of the upper winding of monitoring relay R 270 in such a way that the latter relay releases its armature.

  <Desc / Clms Page number 99>

 



  By releasing its armature, the monitoring relay R 270 interrupts, at contacts 272, the circuit previously drawn for the application of an earth potential to the signal output conductor C 303, so as to cause the de-energization of the relay. output of signals R 397 in powerline carrier switchgear 394 and, consequently, re-energization of the signal input relay R 495 d. in powerline carrier switchgear 494, after which the latter relay interrupts, when operating, to contacts 496, the circuit previously drawn for the application of an earth potential to the signal input conductor C 404, so as to cause the release of the armature of the ring input relay R 450 in the circuit junction 400.

   When releasing its armature, the signal input relay R 450 interrupts, at contacts 452? the previously traced circuit which kept the R 400 bonding relay actuated, so that the latter relay releases its armature a short time later, given that it is of the delayed release type.



  By releasing its armature, the R 400 bonding relay reverses to contacts 401? 402? 403 and 404, the polarity of line conductors C 431 and C 432 of junction 430 with respect to the upper and lower windings of the line relay R 470 so that the right winding & a response relay R 595 in the circuit of junction 500 is polarized so that said relay releases its armature.



   By releasing its armature, the response relay R 595 interrupts, at contacts 597, the circuit previously drawn for the excitation of the lower winding of the monitoring relay R 580, in such a way that the latter relay releases its armature for a short time. later, since it is the delayed release type. By releasing its armature, the R 580 monitoring relay interrupts, at contacts 584, the bonding circuit for energizing the lower winding of the R 590 control relay. However,

  <Desc / Clms Page number 100>

 the latter relay is maintained in its working position due to the closing of the excitation circuit of its upper winding.

   On the other hand, by releasing its armature, the R 580 monitoring relay interrupts, at contacts 581, the excitation circuit previously drawn from the overvoltage battery 616, passing through the lower winding of the pulse bank. R 620 of the junction circuit 500 and the lower and intermediate windings of the signal output relay R 660 of the junction circuit 600. the signal output relay R 660 releases its armature, the pulse relay R 620 occupying its position of rest.



  By releasing its armature, the signal output relay R 660 of the junction circuit 600 interrupts, at contacts 663, the circuit previously drawn for the application of an earth potential to the signal output conductor C 603 which causes the de-energization of the R 697 signal output relay in powerline carrier 694 and re-energization of the R 795 signal input relay in the 794 power line carrier, so that the R 795 signal input relay interrupts, at contacts 796, the circuit previously drawn for the application of an earth potential to the input conductor r'e signals C 704, of material to de-energize the lower winding of the signal input relay R 705 in the junction circuit 700, so that the latter relay releases its armature.

   By releasing its armature, the signal input relay R 705 interrupts, at contacts 707, the multiple circuit previously indicated for switching on the occupancy lamp L 732 and closes, at contacts 706, the circuit previously drawn for the 'excitation of the upper winding of the plug relay R 720 in multiple with its lower winding and in series with the front monitoring relay R 745 in dicorde 766, so that the latter relay being of the marginal type

  <Desc / Clms Page number 101>

   gets excited. While operating, the monitoring relay R 745 closes, at contacts 746, the circuit previously drawn for the ignition of the front monitoring lamp L 747 so as to indicate to the operator of the switchboard 765 that the requested subscriber of the set. T II of the remote exchange 10 hangs up.

   



   On receiving the end of conversation signal, the operator of the switchboard 765 of the main office 40 removes the front plug P 748 of the dicorde 766 of the jack J 730 which interrupts the circuit which kept the front monitoring relay R 745 activated in the dicorde 766 and the plug relay R 720 in the junction circuit 700.



  In addition, when the front plug P 748 is removed from jack J 730, the contacts 731 of said jack are open and interrupt the circuit which kept the jack relay R 710 activated, so that the latter relay releases its armature for a short time. instant later, since it is of the delayed release type.



   By releasing its armature, the plug relay R 720 interrupts, at contacts 721, the circuit previously drawn for the application of a battery potential to the signal output conductor C 703, so as to cause the relay to de-energize. signal output R 797 in powerline carrier equipment 794 and the re-energization of the signal input relay R 695 in carrier current equipment 694, after which this last relay closes at contacts 696, the circuit previously drawn for the application of a battery potential to the signal input conductor C 604, so as to re-energize the signal input relay R 670 in the junction circuit 600.

   By releasing its armature, the relay jack R 710 of the junction circuit 700 interrupts, at contacts 713? the circuit previously drawn for switching on the L 732 opoupation lamp? which indicates that the junction circuit

  <Desc / Clms Page number 102>

   700 is free at this time.



   When operating again, the signal input relay R 670 of the junction circuit 600 closes again, at contacts 671, the previous circuit drawn for the excitation of the upper winding of the pulse relay R 620 in the junction circuit 500, so that the latter relay is energized. When operating, the pulse relay R 620 interrupts, at contacts 622, the circuit previously drawn for the excitation of the upper winding of the control relay R 590 and the multiple circuit for the excitation of the winding of the control relay. R 560 monitoring, so that the indicated relays release their armature a short time later since they are of the delayed release type.

   By releasing its armature, the control relay R 590 interrupts, at contacts 593, the circuit previously drawn for the excitation of the upper winding of the pulse relay R 620, in such a way that the latter relay releases its armature and closes, at contacts 592, the original circuit previously drawn for the excitation of the drive relay R 585, so that the latter operates again.



   On the other hand, when the pulse relay R 620 operates for the first time, it interrupts, at contacts 621, the original loop circuit leading to the line relay R 740 in the junction circuit 400 and when the control relay R 590 releases its armature subsequently, it interrupts, at contacts 591, another point of the loop circuit indicated, so that the line relay R 470 of the junction circuit 400 releases its armature. By releasing its armature, the line relay R 470 interrupts, at contacts 472, the circuit previously drawn which kept the take-off relay R 480 actuated, so that the latter relay releases its armature a short time later, given that it is of the delayed release type.

   By releasing

  <Desc / Clms Page number 103>

 its armature, the bonding relay R 480 interrupts, at contacts 484, the circuit previously drawn which kept the control relay R 490 actuated, so that the latter relay releases its armature. In addition, the bonding relay R 480 closes, at contacts 483, the original circuit previously drawn for the application of a battery potential via the impedance 458 to the control conductor C 433 of the junction. 430. When the earth potential which was applied to the C control conductor 433 of the junction 430 is replaced by a battery potential, the arrival selector 434 is released.



  The earth potential which was applied to the control conductor C 523 of junction 520 is nsi eliminated, which de-energizes the left winding of the response relay R 595 and the upper winding of the switching relay R 630 in the junction circuit 500, so that the switching relay R 630 releases its armature, the response relay R 595 having already released its own.

   By releasing its armature, the switching relay R 630 interrupts, at contacts 638, the circuit previously drawn for the application of an earth potential to the control conductor C 513 of junctions 510 and 515 and closes again, at contacts 639. , the original circuit previously drawn for the application of a battery potential via the resistor 617 to the control conductor C 513 which again indicates the junctions 510 and 515 as free to the selector of the seeker-selector junctions 426 etc ... and arrival selectors 429, etc ... which have access to said junctions.



   Moreover, when the line relay R 470 of the junction circuit 400 releases its armature, it interrupts, at contacts 473, the circuit previously drawn for the application of an earth potential to the output conductor of signals C 403 of so as to de-energize the relay signal output R 497 in the switchgear, current

  <Desc / Clms Page number 104>

 carrier 494 and, consequently, re-energizing the signal input relay R 395 in the current carrier switchgear 394, so that the latter relay interrupts, at contacts 396, the circuit for the application of an earth potential at the signal input conductor C 304 so as to de-energize the signal input relay R 350 in the junction circuit 200.

   By releasing its armature, the signal input relay R 350 interrupts, at contacts 352, the circuit previously drawn which kept the collaborator relay R 340 actuated, so as to cause the de-energization of this last relay for a short time. later. On the other hand, the signal input relay R 350 interrupts, at contacts 351, the loop circuit terminating, via junction 230 of incoming selector 206 and junction 207, at connector. urban 205, so that the urban connector 205 is released by causing the release of the arrival selector 206 and the elimination of the ground potential of the control conductor C 233 of the junction 230.

   When the earth potential is thus eliminated, the control conductor C 238 of the junction 230, the right winding of the response relay R 310 and the upper winding of the switching relay R 260 of the junction circuit 200 are de-energized, which causes the armature of the switching relay R 260 to release, the response relay R 310 having already released its own.

   By releasing its armature, the switching relay R 260 interrupts, at contacts 267, the circuit previously drawn for the application of an earth potential to the control conductor C 223 of junctions 220 and 225 and closes, at contacts 266, the original circuit previously drawn for the application of a battery potential via impedance 257, to the control conductor C 223, so that the junctions 220 and 225 are indicated as free at the selectors of the junctions

  <Desc / Clms Page number 105>

 finder selector 203, etc ... which have access to these junctions. when the urban connector 205 is thus released, the junction 207 is indicated as free to the arrival selectors 206, etc ... which have access to said junction.

   When city cone ctor 205 is released in this way, line circuit 213 operates by indicating the. subscriber line 211 which terminates at the subscriber station T II as free at the urban connectors 205, etc. which have access to said line.



   At this time, the communication established between the calling operator switchboard 765 of the main office 40 and the called subscriber station T 11 of the remote exchange 10 is interrupted and all the devices interested in said communication are fully released and become- are available for future use.



   From the foregoing, it will be understood that a call from calling operator switchboard 765 at main office 40 can be routed to a prepaid requested station T 12, etc., at remote exchange 10 in a manner. identical.



   URBAN CALLS TO THE CENTRAL IN TANDEN 20
It will first of all be assumed that a call made in a subscriber station such as, for example, the T 21 station of the tandem exchange 20 must be routed to a prepaid station such as, for example, the T 22 station. of said central.



  When the call is initiated, by the calling subscriber station T 21, the line circuit 423 associated with the subscriber line 421 is occupied by the urban connectors 427, etc ... which have access to said line and trigger the call. operation of the distributor 425, The distributor 425 designates a free junction among the seeker-selector junctions and, for example, the seeker-selector junction 426 of the first group to be

  <Desc / Clms Page number 106>

 used at this time so that the searcher of the seeker-selector link 426 attacks the subscriber line 421.



  The subscriber of the calling subscriber station T 21 then dials the call number of the requested prepaid station T 22 call number which can be, for example, "1223. the junction selector" researcher-selector 426 responds to the first digit "1" by selecting the first group of urban connectors comprising in particular the urban connector 427, then in this group, a free urban connector.

   For example, the finder-selector junction selector 426 may select the junction 428 which terminates at the particular city connector 427, after which the particular city connector 427 is made responsive to the next two digits formed on the call dial. of the calling subscriber station T 21. The subscriber of the calling subscriber station T 21 then proceeds to the formation on his call dial of the following two digits "2", and "2" so that the urban connector 427 is actuated and attacks the line 422 which terminates at the requested prepayment station T 22 after which the urban connector 427 tests the line 422 to determine whether said line is free or busy at this time.



   It will first of all be assumed that the requested prepaid shift T 22 is busy at this time. Urban connector 427 tests line 422 which terminates at said set, finds that it is busy and returns a busy tone current to junction 428, seeker-selector junction 426 and the subscriber line. 421 to the calling subscriber station T 21, so as to indicate to the subscriber of said station that the desired call cannot be obtained at this moment because of the occupation condition of the requested prepaid station T 22. The subscriber of the calling subscriber station T 21 then proceeds to hang up his apparatus in a manner which will be explained later in a more detailed form.

  <Desc / Clms Page number 107>

 



   It will now be assumed that, on the other hand, the requested prepayment station T 22 is free at the time considered. The urban connector 427 then applies an inrush current on the line 422 terminating at the requested prepayment station T 22 and sends back a caller alert tone current of the called party's call on junction 428 and from there to calling subscriber station T 21, so as to indicate to the subscriber of said station that the requested prepaid station T 22 is called.



  When someone answers the call at the requested prepayment set T 22, the urban connector 427 operates by reversing the polarity of the junction 428 and the selector searcher junction 426, activates the counter (not shown) associated with the line 422, so as to count the conversation in a conventional manner, At this time, a communication is established between the calling subscriber station T 21 and the prepaid station called T 22 and the conversation between these two stations s 'performs in the Usual manner.



     At the end of the communication established when the user of the prepayment set T 22 hangs up, the urboin connector 427 again inverts the polarity of the junction 428, but without effect at this time. Subsequently, when the subscriber of the calling subscriber station T 21 hangs up, the loop circuit leading to the city connector 427 is interrupted so that the city connector 427 and the searcher-selector junction 426 are released. when the ubbain connector 427 is thus released, the line 422 which ends at the prepayment station T 22 is again indicated as free by the line circuit 423 associated with the urban connectors 427, etc ... which have access to said line.

   Similarly, when the selector finder junction 425 is thus released, the subscriber line 421 which terminates at the subscriber station T 21 is indicated as free by the circuit from the line 423 to the city connectors 427, etc. who have access to said post.

  <Desc / Clms Page number 108>

 



  On the other hand, when the finder-selector junction 426 is thus released, the junction 428 which ends at the urban counter 427 is indicated as free at the finder-selector junctions 426 etc., which have access to said junction. At this moment, the communication established between the calling subscriber station T 21 and the requested prepayment station T 22 is interrupted and all the devices interested in said communication are completely released and become available for subsequent use.



   From the above, it will be understood that a call can be routed from the requesting subscriber station T 21 of the tandem exchange 20 to another requested subscriber station of said exchange in an identical manner. . On the other hand, it will be understood that a call leaving from a prepaid station T 22 of the tandem exchange 20 can be routed to a called subscriber station T 21, etc ... or to another prepaid station. called from said exchange in a substantially identical manner.



  It will be observed, with regard to the routing of a call between the requesting prepaid station T 22 of the tandem exchange 20 and a called subscriber station or another prepaid station requested from said exchange, only when the call is the subject to a response, the urban connector 427 operates by reversing the polarity of junction 428 on the selector finder junction used and line 422 with respect to the T 22 prepayment station. This polarity reversal on the requesting prepayment station T 22 causes a blocking of the transmitter of the requesting prepayment station T 22 by the associated copper oxide rectifier unless the person using the T 22 prepayment station has at this time introduced the token into this device necessary.

   More precisely, in the case where the person wishing to use the requesting prepayment set T 22 has not entered the necessary token at this time, he can hear the person of the requested subscriber set or

  <Desc / Clms Page number 109>

 from the prepaid station requested from the 20 mwis tandem exchange she cannot speak to said person because the copper oxide rectifier blocks the associated transmitter due to the polarity reversal on the prepaid station - claimant T 22.

   On the other hand, when the person wishing to use the requesting prepayment station T 22 introduces a token into this device, the copper oxide rectifier stops blocking the emitter from said device, so that the
 EMI109.1
 communication is established in the manner described above.



  APPEL P'10VJJN '): Fr D'IJN POSif1E D' éiBo NN1l or TI'UN} JOS'JT3. 'Il PFtûFrI; Nm' DU C'NT ill? IùT3Y 20 ET. OF Sif1INE;. ONE POSTE TI '.l130NNE OR 1 ONE I-DSreE .1 P1P J..IEIBNT DU CEUTR11L ZliOIGNEi IJ
It will first of all be assumed that a call made in a subscriber station such as, for example, the subscriber station T 21 of the tandem exchange 20, must be routed to a subscriber station such as, for example , the subscriber station T II of the remote exchange 10.

   When the call is initiated at the calling subscriber station T 21, the line circuit 423 associated with the subscriber line 421 operates in such a way that said line is indicated as busy at the urban connectors.
 EMI109.2
 427, etc, ... which have access to said line in such a way that the operation of the distributor 425 is triggered. the distributor 425 designates among the finder-selector junctions one of them free at this moment, such as the selector finder junction 426 of the first group, so that the selector finder of the junction 426 attacks the subscriber line - born 421.



   The subscriber of the calling subscriber station T 21 of the tandem exchange 20 then forms on its dial an indicative number such as, for example, the number "9" indicating that the call must be routed to the remote exchange 10, this number being

  <Desc / Clms Page number 110>

 followed by the call number of the requested subscriber station 1 ... 1! of the remote exchange 10, call number which can be for example "III". Thus, the subscriber of the calling subscriber station T 21 first of all forms the indicative number "9" on his dial. At this moment, the selector of the selector finder junction 426 responds to the first digit "9" by selecting the corresponding bundle of junctions comprising in particular the junction 430 then, in this bundle, a free junction.

   For example, the selector finder junction selector 426 may select the particular junction 430 assuming that the junction circuit 400 is free at this time. The particular junction 430 is indicated as free to the selector of the seeker-selector junction 426 by applying a battery potential to the control conductor C 433 of said junction.



   Specifically, a battery potential is normally applied through impedance 458 and contacts 466 and 483 to the C control conductor 433 of junction 430.



   On the other hand, when the selector seeker junction selector 426 drives junction 430, the previously traced loop circuit is closed for energizing the upper and lower windings of line relay 470 in junction circuit 400, so that this latter relay operates and drives the junction circuit 400 in the manner previously discussed. when the junction circuit 400 is thus driven, the driving of the power line apparatus 494 of the tandem exchange 20 is carried out in such a way as to cause the attack by the line 60 of the power line apparatus 394 of the remote exchange 10.

   The trunk circuit 200 is then driven and itself drives the arrival selector 206 of the remote exchange 10, all in the manner described above.

  <Desc / Clms Page number 111>

 



   The subscriber of the calling subscriber station T 21 of the tandem exchange 20 then forms on its dial the three digits "I", "I" and "I" composing the call number of the called subscriber station T II of the remote central 10. The digits shown are transmitted over the loop circuit previously drawn to line relay R 470 of junction circuit 400 and individually subtracted from powerline carrier 494. From there, said digits are retransmitted by line 60 to the power line carrier 394, and from there to the signal input relay R 350 of the junction circuit 200 and then to the junction 230, all in the manner described above.

   The arrival selector 206 responds to the first digit "I" by selecting the first group of urban connectors comprising in particular the urban connector 205 then, in this group, a free urban connector. For example, the arrival selector 206 can select the junction 207 leading to the urban connector 205 which is then made sensitive to the next two digits "I" and "I" received through the junction 230 of the arrival selector 206 and junction 207; so that the urban connector 205 is actuated and drives the subscriber line 211 terminating at the subscriber station T II of the remote exchange 10 after which the urban connector 205 tests the subscriber line 2II to determine if she is free or busy at this time.



   It will first of all be assumed that the called subscriber station T II of the remote exchange 10 is busy at this time.



    Urban connector 205 tests subscriber line 2II terminating at said station, finds that it is busy and returns a busy tone current through junction 207, arrival selector 206 and junction 230 of the call circuit. junction 200.

   This busy tone current is fed back from junction circuit 200 to powerline carrier equipment 394, such that the latter transmits a corresponding carrier signal through

  <Desc / Clms Page number 112>

 line 60 to powerline carrier 494, after which powerline carrier 494 returns the busy tone current to junction circuit 400 and from there through junction 430 to Seeker-selector link 426 and from the subscriber line 421 to the requesting subscriber station T 21 of the tandem exchange 20, all in the manner described above.

   The subscriber of the calling subscriber station T 21 of the tandem exchange 20, by receiving the busy signal, proceeds to hang up his apparatus in a manner which will be explained below in more detail.



   It will be assumed, on the other hand, that the requested subscriber station T II of the remote exchange 10 is free when the urban connector 205 selects the subscriber line 211 which terminates at said station. The urban connector 205 then applies an inrush current to the subscriber line 211 terminating at the requested subscriber station T II of the remote exchange 10; which causes the line circuit 213 associated with the subscriber line 211 to operate, indicating that the subscriber line 211 is busy at the other city connectors of the associated group.

   In addition, the city connector 205 sends back a caller ID warning tone stream on the junction 207 and the circuit previously drawn to the calling subscriber station T 21 of the tandem exchange 20, so as to indicate to the subscriber of said station that the subscriber of the called subscriber station T II of the remote exchange 10 is called.



   When the subscriber of the called subscriber station T II of the remote exchange 10 answers the call, the urban connector 205 reverses the polarity of the junction 207 and, consequently, that of the junction 230, so as to cause the operation of the response relay R 310 in the circuit

  <Desc / Clms Page number 113>

 switch 200, so that the powerline switchgear 394 is controlled such that it sends a response signal on line 60 back to the powerline switchgear 494. The powerline switchgear 494 triggers then the operation of the signal input relay R 450 in the junction circuit 400, all in the manner explained above.

   The R 450 signal input relay then causes the R 400 bonding relay to operate, which reverses the polarity of junction 430 with respect to the upper and lower windings of the line relay R 470 of the junction circuit 400, as before. exposed.



  This reverse polarity of the junction 430, and therefore of the researcher-selector junction 426 triggers the operation of the counter (not shown) associated with the line 421 of the calling subscriber, so as to ensure the counting of the communication between the calling subscriber station T 21 of the tandem exchange 20 and the calling subscriber station T II of the remote exchange 10. At this time, a call is established between the calling subscriber station T 21 of the central exchange. tandem 20 and the called subscriber station T II of the remote exchange 10 and the conversation between these two stations takes place in the manner described above.



   At the end of the established communication, when the subscriber of the called subscriber station T II of the remote exchange 10 hangs up, the urban connector 205 again inverts the polarity through the junction 207 and the arrival selector 206 on the conductors of line C 231 and C 232 of the junction 230, so that the left winding of the response relay R 310 of the junction circuit 200 is polarized in such a way that it releases its armature, which causes the release of that of the signal output relay R 397 in the power line carrier 394, and, consequently, a new operation of the signal input relay R 495 of the power line carrier 494.

   In this way, the input relay

  <Desc / Clms Page number 114>

 of signals R 450 of the junction circuit 400 is de-energized all in the manner explained above. By releasing its armature, the R 450 signal input relay causes the R 400 bonding relay to de-energize, so that the latter relay again reverses the polarity on junction 430 with respect to the upper and lower windings of the line relay R 470 but without effect at this time, all as explained above.



   When the subscriber of the calling subscriber station T 21 of the tandem exchange 20 then hangs up his apparatus, the previously traced loop circuit which kept the line relay R 470 of the junction circuit 400 activated is interrupted. By releasing its armature, the line relay R 470 causes the release of the junction circuit 400 and, consequently, the de-energization of the signal output relay R 497 of the power line carrier 494, so that the relay signal input R 395 of powerline carrier 394 is actuated again and causes de-energization of signal input relay R 350 of junction circuit 200.

   By releasing its armature, the signal input relay R 350 causes the release of the junction circuit 200 and, consequently, of the arrival selector 206 and of the city connector 205, all in the manner set out above. At this moment, the communication established between the calling subscriber station T 21 of the tandem exchange 20 and the called subscriber station T II of the remote exchange 10 is interrupted and all the devices interested in this communication are completely released and become available for later use.



   From the foregoing, it will be understood that a call can be routed between a calling subscriber station T 21, etc ... of the tandem exchange 20 and a station

  <Desc / Clms Page number 115>

 prepayment requested T 12 etc .... from the remote exchange 10 in an identical manner.



   It will also be understood that a communication can be established between a prepaid calling station T 22, etc. of the tandem exchange 20 and a called subscriber station T 11, etc. or a prepaid requested station T 12. , ect ... of the remote central 10 in a substantially identical manner.



   It will be observed, with regard to the routing of a call between the requesting prepaid station T 22 of the tandem exchange 20 and a called subscriber station or a requested prepaid station of the remote exchange 10, that when the call is answered, the devices operate in such a way that the bonding relay R 400 of the junction circuit 400 is actuated so that the polarity of junction 430 is reversed with respect to the upper and lower windings of the relay of line R 470 in the junction circuit 400, the whole in the manner explained above.

   This polarity reversal on the junction 430 and on a selector finder junction such as, for example, the junction 426 and the line 422 leading to the prepaid station T 22 cause the transmitter of the prepayment station T 22 to be blocked by the associated copper oxide rectifier, unless the person wishing to use the T 22 prepayment station has introduced the necessary token into this device at this time.

   More precisely, in the event that the person wishing to use the requesting prepaid set T 22 has not entered the necessary token into this device at this time, he or she can hear the person of the requested subscriber set or of the requested prepaid set. of the remote exchange 10, but it cannot enter into conversation with it due to the fact that the copper oxide rectifier blocks the associated transmitter as a result of the polarity inversion on the requesting prepayment station T 22. On the other hand, when the person, wishing to use the requesting prepayment station

  <Desc / Clms Page number 116>

 T 22 introduces a token into this apparatus, the copper oxide rectifier no longer blocks the emitter of said apparatus so that communication can be established in the manner explained above.



   CALL FROM A SUBSCRIBER SET OR A
TANDEM 20 CENTRAL PREPAYMENT STATION - AND INTENDED FOR THE OPERATOR'S PANEL
OFFICE 40
It will first be assumed that a call initiated by a subscriber station such as for example the subscriber station T 21 of the tandem exchange 20, must be routed to the operator switchboard 765 of the main office 40 It will be assumed, on the other hand, that the searcher of the searcher-selector junction 426 has attacked the subscriber line 421 terminating at the T 21 set of the calling subscriber and that the selector of the searcher-selector junction 426 is conditioned. in such a way that it is sensitive to the first digit formed on the call dial.

   The subscriber of the calling station T 21 of the tandem exchange 20 then forms on his dial the single digit designated as the call number of the operator panel 765 of the main office 40. This single digit may be "0" for example. When the number "0" is thus formed on the call dial of the calling station T 21 of the tandem exchange 20, the selector of the searcher-selector junction 426 responds to this figure by selecting the bundle of junctions including in particular junction 510 , then in this beam a free function.

   For example the selector of junction 426 can select the particular junction 510 which terminates in circuit 500, junction 510 being indicated as free by the application of a battery potential to the control conductor c 513 of said junction via contacts 578 and

  <Desc / Clms Page number 117>

 639 and resistor 617. A loop circuit is also closed between the calling subscriber station T 21 of the tandem exchange 20 and the upper and lower windings of the line relay R 610 of the junction circuit 500.

   This loop circuit is drawn as follows: earth, lower winding of line relay R 610, contact 634, winding 652 of translator RC 650, line conductor C 513 of junction 510 and battery, upper winding of line relay R 610 , contact 652, winding 651 of the RC 650 translator, line conductor 0 511 of the junction 510. The line conductors C 511 and C 512 of the junction 510 are connected through the searcher junction selector 426 and the line subscriber 421 to the calling subscriber station T 21 of the tandem exchange 20.

   When the loop circuit traced above is thus closed, the line relay R 610 of the junction box 500 operates and causes the drive of the junction circuit 500 of the tandem exchange 20 via the transmission line. junction 665 of junction circuit 600 of repeater 30, which causes the signal output relay R 660 of the junction circuit 600 to be energized and the corresponding operation of the signal output relay R 697 of the device Powerline carrier 694 disposed at repeater 30 such that through line 70 the signal input relay R 795 of carrier equipment 794 at main office 40 is deenergized.

   In this way the signal input relay R 705 of the junction circuit 700 is energized, indicating the presence of a call waiting on the junction circuit 700, this call being intended for the attendant switch board 765. whose operator must answer said call in the manner described above. The operator at switchboard 765 in main office 40 can answer the call by

  <Desc / Clms Page number 118>

 Using the 766 dicord, inserting the front P 748 plug into the J 730 jack which terminates the 700 junction circuit. This energizes the R 710 jack relay and the R 720 plug relay of the 700 junction circuit of the manner explained previously.

   The junction circuit 700 causes the signal output relay R 797 of the powerline carrier equipment 794 to operate and consequently the de-energization of the signal input relay R 695 of the power line carrier 694, from so that the signal input relay R 670 of the junction circuit 600 releases its armature, all in the manner previously explained '*'
By releasing its armature, the signal input relay R 670 of the junction circuit 600 causes the de-energization of the pulse relay R 620 of the junction circuit 500 and, consequently, the operation of the monitoring relay R 560 of the junction circuit 500 as explained above.

   When operating, the R 560 monitoring relay causes the R 550 time relay to operate, which in turn causes the R 540 time relay to operate after a predetermined time interval, after which the R 540 time relay causes de-energization. of the time relay R 550 and the energization of the battery changeover relay R 530, all in the manner described above.



  When operating, the battery reversing relay R 530 reverses the polarity of the junction 515 leading to the junction circuit 500, as explained previously, but does not reverse that of the line conductors C 511 and C 512 of the junction 510 with respect to the upper and lower windings of the line relay R 610 of the junction circuit 500. As a result, the polarity of the junction 510 is not reversed and, therefore, the polarity of the line 421

  <Desc / Clms Page number 119>

 terminating at the calling subscriber station T 21 of the tandem exchange 20 is not reversed either, so that the counter (not shown) associated with the subscriber line 421 is not activated.

   Accordingly, the call originating from the calling subscriber station T 21 of the tandem exchange 20 and arriving at the operator switch board 765 of the main office 40 is an untaxed call.



   During the time when the timing relay R 550 of the junction circuit 500 occupies its working position, the upper winding of the tone relay R565 is bypassed through contacts 552 and 554 and capacitor 525 on the terminals. line conductors C 511 and C 512 of junction 510, however without effect since no tone current passes through the lower winding of the tone relay R 565, since the call in question comes from the set. 'calling subscriber T 21 of the tandem exchange 20, so that no category tone is applied to the control conductor C 513 of the junction 510.



   At this time, a communication is established between the calling subscriber station T 21 of the tandem exchange 20 and the called operator switchboard 765 of the main office 40, so that the operator of the switchboard 765 is informed accordingly. which concerns the routing of the call and then proceeds to this routing using the rear plug P 758 of the dicorde 766 in the manner described previously.



   At the end of the established communication, when the subscriber of the calling subscriber station T 21 of the tandem exchange 20 hangs up, the previously drawn loop circuit which kept the line relay R 610 activated in the junction circuit 500 is interrupted. , so

  <Desc / Clms Page number 120>

 that the latter relay releases its armature by causing the de-energization of the R 660 signal output relay in the junction circuit 600 in the manner explained previously By releasing its armature, the R 660 signal output relay causes the output relay to de-energize of signals R 697 in power line carrier 694 and, consequently, a new operation of the signal input relay R 795 in power line carrier 794, so that the signal input relay R 705 of the junction circuit 700 is de-energized,

   all in the manner explained above. When the signal input relay R 705 is thus de-energized, the front monitoring relay R 745 of the dicorde 766 is actuated again, which causes the front monitoring lamp L 747 to come on, indicating to the operator of the switchboard 765 of the main office 40 when the subscriber of the calling subscriber station T 21 of the tandem exchange 20 has hung up.



   The operator of the switchboard 765 of the main office 40 then removes the front plug P 748 from the jack J 730 causing the de-energization of the plug relay R 720 and the jack relay R 710 in the junction circuit 700 and, consequently, de-energization of the signal output relay R 797 of the power line carrier 794 so that the signal input relay R 695 of the power line carrier 694 is energized again, causing a new energization of the signal input relay R 670 of the junction circuit 600 and, consequently, a new operation of the pulse relay R 620 of the junction circuit 500, all in the manner described above.

   When operating again, the pulse relay R 620 releases the junction circuit 500 and consequently that of the researcher junction -

  <Desc / Clms Page number 121>

 selector 426, so that the circuit 423 associated with the subscriber line 421 is actuated indicating again that the subscriber line 421 which terminates at the subscriber station T 21 of the tandem exchange 20 is free at the city connectors 427 , etc ... who have access to said station.



   At this moment, the communication established between the calling subscriber station T 21 of the tandem exchange 20 and the called operator switchboard 765 of the main office 40 is interrupted and all the devices interested in said communication are completely released and de- come available for later use.



   From the foregoing, it will be understood that a communication can be established between a requesting prepaid station such as, for example, the T 22 station of the tandem exchange 20 and the requested operator switch board 765 of the office. main 40 in an identical manner. However, it will be observed that, when the selector of the selector searcher junction used, such as for example junction 426, operates in response to the single digit "0" formed on the call dial of the requesting prepaid station T 22 by selecting a free junction in the bundle comprising junction 510 and, for example, junction 510 itself which terminates at junction circuit 500, an additional operation takes place.

   More precisely, given that the call in question originates at the T 22 prepayment set of the tandem exchange 20, a tone potential is applied from the line circuit 424 associated with the line 422 which terminates at said set, via the seeker-selector junction 426, to the C control conductor 513 of the junction 510, so that the lower winding of the tone relay R 565, is energized by a tone current in the case considered. The tone current

  <Desc / Clms Page number 122>

 crossing the lower winding of the tone relay R 565 causes the induction of a corresponding tone voltage in the upper winding of said relay but has no effect at this time.



   Subsequently, when the operator of the switchboard 765 answers the call on the junction circuit 700 by inserting the front plug P 748 of the dicorde 766 into the jack, J730 terminating the junction circuit 700, assuming that the indicated device is used in the communication envisaged, this apparatus operates in the manner previously explained, so that the time relay R 550 of the junction circuit 500 operates first of all and then, a short time later, the time relay R 540 in turn works by causing the R 550 time relay to de-energize as explained previously.

   During the time interval when the time relay R 550 occupies its working position, as indicated above the upper winding of the tone relay R 565 is bypassed on the line conductors C 511 and C 512 of the junction 510 said junction 510 being included in the previously traced connection which terminates back at dichord 766 of the operator switch board 765 of the main office 40; so that a tone current is returned to the headset 767 of the attendant switch panel 765, so as to indicate to the operator of said panel that the call in question originates at a prepaid set of the central office in tandem 20.

   Subsequently, when the time relay R 540. of the junction circuit 500, operates, it causes the de-energization of the time relay R 550, as indicated above, which stops the application of the category tone to the panel d. operator requests 765 from main office 40.



   This tone signal indicates to the operator of the requested switchboard 765 of the main office 40 that

  <Desc / Clms Page number 123>

 the call which is the subject of an answer at this moment at its origin in a prepaid set of the tandem exchange 20, which reminds the operator that she must ask the person using the calling prepaid set T 22 of the tandem exchange 20 to introduce the necessary tokens into this device after routing the call to the desired destination.

   Of course, when the tokens are subsequently introduced into the requesting prepayment station T 22 of the tandem exchange 20, this device operates by transmitting identification tones over the connection established in a manner identical to that described above. at main office switchboard 765 40.



   CALL FROM THE OPERATOR SWITCH PANEL
FROM MAIN OFFICE 40 AND FOR A SUBSCRIBER POSITION
OR AT A POST WITH PREPAYMENT OF THE TANDEM CENTRAL 20
It will first be assumed that the operator of the switchboard 765 of the main office 40 has answered a call using the back plug P 758 of the dicorde 766 said call to be transmitted to a called subscriber station such as, for example, the subscriber set T 21 of the tandem exchange 20. The operator inserts the front plug P 748 of the dichord 766 into a jack terminating a free junction circuit of the group comprising the junction circuit 700.

   Assuming that said junction circuit 700 is free at this time and that the front plug P 748 of dichord 766 is inserted into the J 730 jack which terminates said circuit by the operator of the requesting switchboard 765 of the main office 40 , the junction circuit 700 is activated and drives the power line equipment 794 of the main office 40, so that the power line equipment 694

  <Desc / Clms Page number 124>

 of repeater 30 is driven by line 70 and itself drives trunk 600.

   The junction circuit 500 is in turn driven by the junction line 665 connecting the repeater 30 to the tandem exchange 20 and said junction circuit 500 in turn drives the arrival selector 434 through the junction 520, all from the manner explained above.



   Since the call in question must be routed to the subscriber station T21 request of the tandem exchange 20 the operator of the switchboard 765 of the main office 40 can directly dial the call number of the subscriber station on her dial. requested T 21 from the tandem exchange 20, call number which can be for example "I2I". More precisely, the dialing disk of the call dial D 760 of the dicorde 766 is operated by the operator at the switchboard 765 'and the three digits "1", "2" and "I" are transmitted on the connection. established and retransmitted by the junction circuit 500 on the junction 520,

   all in the manner explained above. The arrival selector 434 responds to the first digit "I" transmitted on the junction 520 by selecting the first group of city connectors including in particular the city connector 427. For example, the arrival selector 434 can precisely select the junction. 428 which terminates in the city connector 427, so that the city connector 427 is made sensitive to the next two digits transmitted on the junction 520. The city connector 427 then responds to the digits "2" and "I" by selecting the subscriber line 421 which ends at the called subscriber station T 21 of the tandem exchange 20.

   The urban connector 427 then tests the requested subscriber station T 21 according to the usual practice to determine whether said poet is free or busy.



   In the event that the called subscriber station T 21 of the tandem exchange 20 is busy at this time, the

  <Desc / Clms Page number 125>

 line 423 which belongs individually to the subscriber line 421 leading to said set to indicate the condition observed to the urban connector 427. The urban connector 427 ensures the return of a busy tone current to the trunk 428 and the selector arrival 434 and, from there, by the previously traced connection, to the headset 767 of the requesting operator switchboard 765 of the main office 40, all in the manner set out above.



   It will be assumed, on the other hand, that the requested subscriber station T 21 of the tandem exchange 20 is free when the urban connector 427 selects the subscriber line 421 terminating at said station. The urban connector 427 then applies an inrush current to the subscriber line 421 terminating at the requested subscriber station T 21 and causes the line circuit 423 associated with the subscriber line 421 to operate in such a way that the line subscriber 421 is indicated as busy to the other urban connectors of the associated group.

   In addition, the city connector 427 returns a caller ID warning tone stream of the called party to the. junction 428, the incoming selector 434 and the connection previously traced, to the headset 767 of the calling operator switch panel 765 of the main office 40, so as to indicate to the operator of said panel that the subscriber of the called subscriber station T 21 of the tandem exchange 20 is called, all in the manner described above.



   When the subscriber of the called subscriber station T 21 of the tandem exchange 20 answers the call, the urban connector 427 reverses the polarity of the junction 428 and, consequently, that of the line conductors C 521 and C 522 of junction 520, so that the right winding of response relay R 595 of junction circuit 500 is biased such that said relay operates.



  When operating, the R 595 response relay causes the

  <Desc / Clms Page number 126>

 tation of the junction circuit 500 monitoring relay R 580 and therefore the operation of the R 660 signal output relay of the junction circuit 600. The junction circuit 600 then controls the powerline carrier 694, and hence the powerline carrier equipment 794, so that the junction circuit 700 is controlled in such a way that it gives the operator of the switchboard 765 of the main office 40 response monitoring signals. . At this time, a communication is established between the calling operator switchboard 765 of the main office 40 and the called subscriber station T 21 of the tandem exchange 20.



   At the end of the established communication, when the subscriber of the called set T 21 of the tandem exchange 20 hangs up, the apparatus operates in such a way as to give the calling switch panel 765 of the main office 40 an end of conversation signal. to handle it? previously exposed.



  Subsequently, when the operator of the switchboard 765 removes the front plug P 748 of dicorde 766 from the J 730 jack which terminates the junction circuit 700, the junction circuit 700, the powerline carrier equipment 794, the current equipment carrier 694, trunk circuit 600, trunk circuit 500 and arrival selector 434 are released, all in the manner previously discussed. When the arrival solector 434 is thus released, the city connector 427 is also released, so that the line circuit 423 indicates that the subscriber line 421 which terminates at the subscriber station T 21 is free. to urban connectors 427, etc .... which have access to said line.



   At this moment, the communication established between the requesting switchboard 765 of the main office 40 and the called subscriber station T 21 of the tandem exchange 20 is interrupted and all the devices interested in said communication are completely released and become available for later use.

  <Desc / Clms Page number 127>

 



   From the above, it will be understood that a call from the calling operator switchboard 765 of the main office 40 can be routed to a prepaid requested station T 22 etc ... of the tandem exchange 20 in a manner. identical.



     BISTER WARNING SYSTEM OPERATION
THE REPEATER 30 AND THE MAIN OFFICE 40. -
Since the repeater 30 is unmonitored, it is necessary to provide, in combination with the powerline equipment connecting the repeater 30 to the main office 40, a warning system.

   The elements of this system associated with the carrier current channel comprising the carrier current apparatus 694 arranged at the repeater 30 and the carrier current apparatus 794 arranged at the main office 40 and interconnected by the line 70 comprising the pulse transmitter warning signal 680 located at repeater 30 and warning signal repeater 770 located at main office 40, as previously indicated. When the junction circuit 600 is free, the signal input relay R 670 of this circuit normally occupies its operating position and the signal output relay R 660 normally occupies its rest position, so that a switching circuit bonding is closed at contacts 674 and 664.

   Said circuit which comprises the contacts 687 and the set of contacts S 684 keeps the starting relay R 686 of the warning pulse transmitter 680 actuated. The starting relay R 686 maintains, at the contacts 686, a connection. established between the motor 681 and the commercial single-phase alternating energy source, so that the motor 681 keeps interrupted, while operating, the set of switching springs S 682, and on the other hand actuates the gearbox 683 .



  * At any time while the engine 681 of the warning pulse transmitter 680 is running, if the

  <Desc / Clms Page number 128>

 junction circuit 600 comes under attack, one of two things, either the R 670 signal input relay releases its armature, or the R 660 signal crimp relay attracts its own, as explained previously, this which interrupts, at the corresponding contacts 674 or 664, the previously drawn bonding circuit which kept the starting relay R 686 of the warning pulse transmitter 680 actuated, so that the latter relay releases its ar- tives a short time later, since it is of the delayed release type.

   By releasing its armature, the starting relay R 686 interrupts, at contacts 687, another point of the bonding circuit for the excitation of its winding and interrupts, at contacts 688, the excitation circuit of the motor 681, so that the motor 681 stops again by closing the set of switching springs S 682 and returning the gearbox 683 to its normal position.

   Subsequently, when the junction circuit 600 becomes free again, the signal input relay R 670 operates again and the signal output relay R 660 releases its armature, so that the contacts 674 and 664 are closed again. , which completes a circuit comprising the set of switching springs S 682 and the contacts S 684 for energizing the starting relay R686, so that the latter relay operates again by closing, at contacts 687, its circuit bonding previously drawn and by closing, at the contacts 688, the circuit previously drawn for the excitation of the motor 681. When the operation of the motor 681 is thus triggered,

   the switching spring set S 682 opens again and the operation of the gearbox 603 resumes from its normal position.



   From the above, it will be understood that in

  <Desc / Clms Page number 129>

 In the event that the junction circuit 600 remains free for a predetermined time interval, the motor 681 of the warning pulse transmitter 680, while operating during said interval, drives the gearbox 683 away from it. from its normal position and bringing it to its limit position, so that the contacts S 684 are open and the contacts S 685 closed. When the S 684 contacts are open, the previously traced bonding circuit which kept the R 686 starting relay actuated is interrupted, so that the latter relay releases its armature a short instant later, since it is on. delayed release type as indicated above.

   When contacts S 685 are closed, a circuit is established through contacts 687, 664 and 674 for the application of an earth potential to the signal output conductor 0 603 during the brief time interval in which the starter relay R 686 releases its armature. However, when the starter relay R 686 releases its armature, it interrupts, at contacts 687, the circuit previously drawn for the application of an earth potential to the signal output conductor 0 603 via the circuit traced above.

   As a result, an earth potential is applied to the C signal output conductor 603, and then removed from said conductor a short time later, so that the signal output relay 1697 of the powerline carrier 694 attracts its signal. armature, then release it for a very short time.



  In addition, when the starter relay R 686 releases its armature, it interrupts, at contacts 688, the excitation circuit of the motor 681, so that the motor 681 stops by closing the set of switching springs S 682 so as to initiate a new operation of the starting relay R 686 in the manner described above. Furthermore,

  <Desc / Clms Page number 130>

 when the motor 681 stops, the gearbox 683 is returned from its limit position to its normal position by interrupting, at contacts S 685, another circuit point previously drawn for the application of earth potential at the 0 603 signal output conductor and closing contacts S 684, so as to re-energize the starter relay R 686, as described above.

   Accordingly, as long as the junction circuit 600 remains free, the warning pulse transmitter 600 operates continuously causing intermittent energization and immediate de-energization of the signal output relay R 697 in the switchgear. carrier current 694. This intermittent operation of the R signal output relay 697 constitutes a periodic warning signal. The periodicity of the warning signal is determined by the character of the gearbox 683 which, for example, can travel its operating stroke between its normal position and its limit position in a time interval of ten minutes. .

   Accordingly, the warning pulse transmitter 680 operates by transmitting the warning signal every ten minutes as long as the junction circuit 600 is free, for the entire indicated time interval.



   Each time the signal output relay R 697 of the powerline carrier 694 switches on and then releases its armature under the control of the warning pulse sender 680, the carrier signal at 24.55 kilo- cycles is transmitted from the power line carrier 694, through line 70, to the power line carrier 794 so as to cause a corresponding de-energization and re-energization of the signal input relay R 795 of said apparatus, so that the R 795 signal input relay transmits the warning signals on the C 704 signal input lead to contacts 796.

   More

  <Desc / Clms Page number 131>

 precisely, when the signal input relay R 795 releases its armature and then attracts it again, it closes then interrupts, at contacts 796, the circuit previously drawn for the application of an earth potential to the conductor d 'signal input R 704, so that the lower winding of the signal input relay R 705 of the junction circuit 700 is momentarily energized, however, without effect since the latter relay is slightly delayed attraction, due to the presence of the normally closed circuit passing through the contacts 715 and short-circuiting the upper winding of said relay.

   As a result, the signal input relay R 705 of the junction circuit 700 does not function according to the warning signals received by the signal input relay R 795 of the power line switchgear 794, which prevents the appearance of a false call on trunk circuit 700 which terminates on jack J 730 in front of the operator switchboard 765 in main office 40.



   However, the warning signals received by the signal input relay R 795 of the power line carrier 794 and retransmitted, at the contacts 796, on the signal input conductor C 704, are also transmitted by the 'intermediate the contacts 781 through the upper winding of the start relay R 785 of the warning signal receiver 770, so that the latter relay operates a short time later, since it is of the type with = delayed attraction. While operating, the starting relay R 785 closes, at the contacts 786, a bonding circuit passing through the contacts 793 for the energization of the lower winding of said relay.

   It will be observed here that, the starting relay R 785 of the warning signal receiver 770 being of slightly delayed attraction, it does not work if the signal input relay

  <Desc / Clms Page number 132>

 R 795 of powerline carrier equipment 794 draws its armature and then immediately releases it, as it receives a steeply-flanked pulse of transient current through line 70. The R 705 signal input relay of the circuit Junction 700 also does not function when the R 795 signal input relay of powerline carrier 794 is energized by the specified transient current.

   In addition, the signal input relay R 705 of the junction circuit 700 requires a considerably longer time to operate than the start relay R 785 of the warning signal receiver 770, so that the R 705 signal input relay does not respond to warning signals while R 785 starter relay responds, all in the manner previously discussed.



   When operating, the R 785 starter relay also closes, at contacts 707, a circuit passing through contacts 716, 728 and 782, the set of switching contacts S 777 and contacts 703 for energizing the R 790 bonding relay. When operating, the R 790 bonding relay closes, at contacts 791 ′, a bonding circuit passing through contacts 702, 782, 728 and 716.

   On the other hand, it will be observed here that the bonding relay R 790 is actuated by the previously traced circuit and closes the bonding circuit traced above only when the junction circuit 700 is free, that is to say when the jack relay R 710 and the plug-in R 720 of said circuit occupy their rest position by closing the corresponding contacts 716 and 728. However, this does not impose new conditions for the operation of the signal receiver of warnings 770 which are not already imposed on the warning pulse transmitter 680, since the junction circuit 700 must remain free for the indicated time interval, as the junction circuit 600 remains free during the same time interval.

   Indeed, it will be understood that, when one of these junction circuits becomes occupied, the conditions

  <Desc / Clms Page number 133>

 busy is transmitted to the other, since they are mounted as a single pair and directly linked to each other by the corresponding carrier current devices 694 and 794 interconnected by line 70.



   To return to the operation of the warning signal receiver 770, when operating, the bonding relay R 790 interrupts, at contacts 793, the bonding circuit previously drawn for the excitation and the lower winding of the starting relay R 785, so that the latter relay releases its armature 4 at the end of the warning signal. In addition, the bonding relay R 790 establishes, at contacts 791, a communication between the motor 773 and the commercial source of the single-phase AC power supply, so that the motor 773 operates by opening the sets of switch contacts S 777 and S 778. On the other hand, the motor 773 moves the gearbox 774 away from its final position.

   When the R 785 starting relay releases its armature, it closes, at contacts 788, a point in parallel with the contacts 702 of the bonding circuit of the R 790 bonding relay. When the gearbox 774 has been moved away from its position normal to a first control position as a result of continuous operation. of motor 773, the set of contacts S 775 is closed momentarily, completing an obvious circuit for the energization of the time relay R 700. When operating, the time relay R 700 closes, at contacts 701, a sticking circuit passing through contacts 792. In addition, the time relay R 700 interrupts, at contacts 702, one of the multiple points of the previously traced bonding circuit which kept the bonding relay R 790 activated.



   In the event that the powerline carrier equipment 694 and 794 are functioning satisfactorily, the warning pulse transmitter 680 again acts by transmitting

  <Desc / Clms Page number 134>

 the warning signal on the powerline carrier approximately ten minutes after the last transmission, assuming that the junction circuits 600 and 700 remain free in the meantime.

   When said warning signal is transmitted again from the warning pulse transmitter 680 in the manner previously discussed, the carrier current apparatus 694 causes the carrier current apparatus to operate. so that the starting relay R 785 of the warning signal receiver 770 attracts and releases its armature again, as explained previously. When the starting relay R 785 operates at this moment, it interrupts at contacts 788, the last multiple point of the bonding circuit of the R 790 bonding relay, so that the latter releases its armature.

   However, the R 785 starting relay does not immediately close, at contacts 787, the original excitation circuit of the R 790 bonding relay, given that the drive motor 773 keeps the contacts S 777 open. By releasing its armature, the bonding relay R 790 interrupts, at contacts 791 ', another point of the bonding circuit to said relay and closes, at contacts 793, the bonding circuit previously drawn for the excitation of the lower winding of the starting relay R 785 .

   In addition, the sticking relay R 790 interrupts, at contacts 792, the sticking circuit previously drawn for the time relay R 700, so that the latter relay releases its armature, given that the contacts S 775 are then opened as a result of the drive of the gearbox 774 beyond its first control position due to the continuous operation of the motor 773.



  Finally, by releasing its armature, the bonding relay R 790 interrupts, at contacts 791, the excitation circuit of the motor 773, so that the motor 773 stops by closing

  <Desc / Clms Page number 135>

 the sets of switching contacts S 777 and S 778. When the set of switching contacts S 777 is thus closed, the original excitation circuit previously drawn for the bonding relay R 790 is closed again, since the relay starter R 785 is in its working position.

   When operating again, the sticking relay R 790 again closes, at contacts 791 ', its sticking circuit which passes through the contacts 702 of the de-energized time relay R 700 and interrupts, at contacts 793 the sticking circuit for the energization of the lower winding of the R 785 starting relay, so that the latter relay releases its armature.



  Finally, the bonding relay R 790 closes the excitation circuit of the motor 773 at contacts 791, so that said motor again opens the sets of switch contacts S 777 and S 778. When the motor 773 stops, the gearbox Gear 774 has returned to its normal position so that operation of gearbox 774 between its normal position and its first control position occurs again following initiation of another operating cycle of engine 773 .



   From the foregoing explanation of the mode of operation of the warning signal receiver 770 in conjunction with the warning pulse transmitter 680, it will be understood that the warning pulse transmitter 680, by transmitting a first warning signal, triggers the operation of the warning signal receiver 770.



  Then the warning pulse transmitter 680, by transmitting a second warning signal, stops the operation of the warning signal receiver 770 and starts again said operation immediately after, so that the warning signal receiver 770 operates continuously in repeated cycles every ten minutes under the control of the warning pulse transmitter 680 as long as the junction circuits 600 and 700 remain

  <Desc / Clms Page number 136>

 free and that the carrier current link comprising the carrier current equipment 694, 794 and line 70 is operating satisfactorily.,
Of course, it will be understood that at any time, when one of the junction circuits 600 or 700 becomes occupied, the other is also occupied,

   so that the operation of the warning pulse transmitter 680 on the one hand and that of the warning signal receiver 770 on the other hand cease, so that the pulse transmitter warning 680 and the warning signal receiver 770 are kept in synchronism.



   However, if the powerline line comprising powerline carrier equipment 694, 794 and line 70 is affected by a fault, the warning pulse transmitter 680 does not transmit the warning sign. after each ten minute time interval has elapsed, although trunk circuits 600 and 700 are free. In this particular case, the warning signal receiver 770 operates continuously for a time interval in excess of ten minutes.



  In this case, the motor 773 also runs continuously for a time interval greater than ten minutes, so that the gearbox 774 is shifted from its normal position through its first control position after nine minutes and half and passing through its second control position at the expiration of one more minute. More specifically, the gearbox 774 is driven to its second control position from its normal position within ten and a half minutes of continuous operation of the engine 773.

   When the gearbox 774 reaches its second control position, the contacts S 776 are momentarily closed and complete a circuit passing through the contacts 792 'of the bonding relay R 790

  <Desc / Clms Page number 137>

 energized for operation of warning relay R 780.



  While operating, the warning relay R 780 closes, at contacts 783, a local bonding circuit for said relay which passes through the correction key K 773. On the other hand, the warning lamp L 771 is lit in parallel with the R 780 warning relay energized.

   The switching on of the warning lamp L 771 indicates to the supervisor of the main office 40 that the power line connection comprising the power line switchgear 694 and 794 and the line 70 is faulty and needs repair, after the repair of the power line. powerline carrier link in question, the correction olé K 773 is actuated in such a way as to interrupt the local holding circuit of the warning relay R780, so that the latter relay releases its armature by switching on again. the 770 warning signal receiver is in operation.

   On the other hand, it will be observed in passing that, while the warning relay R 780 is in its working position, it interrupts, at contacts 781, the connection between the signal input conductor C 704 and the upper winding start relay R 785 which prevents any operation of the latter relay during the time when the warning signal receiver 770 is out of service. On the other hand, the warning relay R 780 interrupts at contacts 782, during its operation, the holding circuit of the R 790 bonding relay, so that the latter relay releases its armature by stopping the engine operation 773 for the specified time interval.



   It will also be noted that in the case where the bonding relay R 790 operates under the control of the starting relay R 785 in the manner explained previously but where the motor 773 does not operate for example due to a fault in the- alternative commercial power source, the R 790 bonding relay closes at contacts 793 '

  <Desc / Clms Page number 138>

 a circuit comprising the set of contact switches S 778 for energizing the delayed warning device DA 772.

   It will be observed in passing that the delayed warning device DA 772 is only actuated if its excitation circuit is kept closed for a suitable interval of time corresponding to the fault in motor 773 and opens the circuit. set of switch contacts S 778 after a reasonable time interval depending on the operation of the R 790 gluing relay.



   When the junction circuit 600 is occupied, the signal output relay R 660 occupies its working position and the signal input relay R 670 its rest position, so that the signal output relay R 697 power line carrier 694 occupies its operating position and the signal input relay R 795 of power line carrier 794 occupies its rest position, while in junction circuit 700 the relay signal input R 705, the jack relay R 710 and the plug relay R 720 occupy their operating position, so that the signal output relay R 797 of the power line carrier 794 is at its working position and that the signal input relay R 695 of the current carrier 694 is in its rest position.

   The R 660 signal output relay at work and the R 670 signal input relay at rest in the junction circuit 600 preventing the operation of the motor 681 of the warning pulse transmitter 680, while the relay of jack R 710 and the plug relay R 720 at work in the junction circuit 700 prevent the operation of the sticking relay R 790 and, therefore, the operation of the motor 773 in the warning signal receiver 770.



  However, the R 795 signal input relay at rest

  <Desc / Clms Page number 139>

 causes the start relay R 785 in the warning signal receiver 770 to operate. Consequently, when the junction circuits 600 and 700 become free, the signal output relay R 660 releases its armature , the signal input relay R 670 operates again and the signal input relay R 705, the jack relay R 710 and the plug relay R 720 release their armature.

     When the signal output relay R 660 releases its armature and the signal input relay R 670 operates again, the operation of the motor 681 of the warning pulse transmitter 680 is triggered as shown. previously.

   When the jack relay R710 and the plug relay R 720 release their armature, the bonding relay R 790 is actuated and triggers the operation of the motor 773 in the warning signal receiver 770. The operation of the warning pulse transmitter 680 and that of the warning signal receiver 770 are triggered synchronously as soon as the junction circuits 600 and 700 become free. The warning signal receiver 770 can therefore monitor the powerline link associated with the expiration of the first ten minute time interval when the first warning signal is received from the warning pulse sender. 680.



   From the above, it will be understood that the warning pulse transmitter 680 only transmits the warning signals to the warning signal receiver 770 when the trunk circuits 600 and 700 are free and when the link associated carrier is functioning properly and that, each time the trunk circuits 600 and 700 are attacked, the warning pulse transmitter 680 and the warning signal receiver 770 are released.



  However, since the warning pulse transmitter 680 transmits the warning signals to the receiver

  <Desc / Clms Page number 140>

 warning, when the junction circuits 600 and 700 are free, a lack of periodic reception of the warning signal by the warning signal receiver indicates that the powerline link is in fault and causes the appearance of an appropriate signal to the main office 40 which is monitored by control and maintenance personnel.



   URBAN CALLS TO THE MAIN OFFICE 40.



   It will be assumed first of all that a call initiated by a subscriber station such as, for example, the subscriber station T 41 of the main office 40 must be routed to another subscriber station of said office. When the call is initiated by calling subscriber station T 41, line circuit 842 associated with subscriber line 841 operates by indicating subscriber line 841 as busy to city switch train 844 and train of interurban switches 805 which have access to said line and by triggering the operation of distributor 843. Distributor 843 designates a free part of train of city switches 844 so that the finder of said train operates by attacking the subscriber line 841.



  The subscriber of the calling subscriber station T 41 then forms on his dial the call number of the called subscriber station, which operates the various selectors and then the connector of the train of urban switches 844, said selector connector. the subscriber line which terminates at the requested subscriber station; At this time, the connector in question tests the requested subscriber station to determine whether it is free or busy. The subsequent routing and final termination of the call established between the calling subscriber station T 41 and the called subscriber station of the main office 40 is in accordance with the usual practice.



     CALL FROM A SUBSCRIBER AND DESTINY FOSTE

  <Desc / Clms Page number 141>

 
AT THE MAIN OFFICE OPERATOR'S SWITCH PANEL 40
It will first of all be assumed that a call initiated by a subscriber station such as, for example, the T 41 station of the main office 40 must be routed to the operator switchboard 765 of said office. On the other hand, it will be assumed that the train of city switches 844 has attacked the subscriber line 841 terminating at the calling subscriber station T 41.



  The subscriber of the calling subscriber station T 41 forms on his call dial the single digit designated as the call number of the operator switch table 765 of the main office 40, a single digit which may not be for example "0". The train of city switches 844 responds to the transmission of the single digit "0" by selecting the junction bundle comprising in particular junction 845 and then, in this bundle, a free junction. For example, the city switch train 844 may select the particular trunk 845 terminating at the direct traffic trunk 8 46, so that trunk 846 initiates a call on trunk 847 THAT terminates on 3ack J 848 at the switch board d operator 765.

   The operator of the switchboard 765 selects a free dichord such as, for example, the 766 dicord and answers the call by inserting the rear plug P 758 of said dicorde into the J848 jack which terminates the 847 junction starting from the junction. of direct traffic 846, A communication is then completely established between the calling subscriber set T 41 and the headset 767 of the operator switch panel 765, assuming that the rear conversation key K 735 of the dicorde 766 has been actuated at this time. More precisely, the subscriber of the calling subscriber station T 41 of the main office 40 informs the operator of the switch table 765 as regards the routing of the call.

   The attendant then proceeds to this routing using the front plug P 748

  <Desc / Clms Page number 142>

 of the dichord 766 in an obvious way.



   At the end of the established communication, when the subscriber of the calling subscriber station T 41 of the main office 40 hooks up, the rear monitoring relay R 755 of the dicorde 766 is actuated again and switches on the monitoring lamp again. rear 757 so as to give the operator of switch panel 765 an end of conversation signal.



  The operator of the switchboard 765 then removes the rear plug P 758 of the dichord 766 of the J 848 jack which terminates the junction 847 leading to the direct traffic junction 848, so that the direct traffic junction 846 is released, this which releases the train of city switches, after which the line circuit 842 associated with the subscriber line 841 terminating at the subscriber station T 41 is activated indicating the subscriber line 841 as free at train of interurban switches 805 and to the train of city switches 844 which have access to said line.



     CALL FROM THE OPERATOR SWITCH PANEL
AND INTENDED FOR A SUBSCRIBER POSITION AT THE MAIN OFFICE 40
It will first be assumed that the operator of the switchboard 765 of the main office 40 has answered a call using the front plug P 748 of the dicorde 766 and requiring routing to a called subscriber station such as by example the subscriber set T 41. The operator inserts the rear plug P 758 of the dicorde 766 in a jack terminating a free junction leading to the line of interurban switches 805 such as, for example, the JN807 jack terminating the junction 806 resulting in trunk switch train 805.

   The operator of the switchboard 765 then brings the numbering key X 737 to its rear position, so as to connect the call dial D 760 to the rear plug P 758. The operator of the switchboard 765 proceeds then to the formation on its call dial of the called subscriber set T 41.

  <Desc / Clms Page number 143>

 inter so that the switch / city train 805 operates by selecting the subscriber line 841 which terminates at the called subscriber station T 41. The trunk switch train 805 tests the called subscriber station T 41 to find out. determine whether it is free or busy and, assuming that the requested subscriber station T 41 is free, inrush current is applied by the train of toll switches 805 to the subscriber line 841 which terminates at said station.

   When the subscriber of the called subscriber station T 41 answers the call, a communication is established between the headset 767 of the calling switch table 765 and the called subscriber station T 41, again assuming that the operator of the switch panel 765 has returned the dialing key K 737 to its normal position and then activated the rear conversation key L 735.

   The operator of the switch panel 765 notifies the subscriber of the called subscriber station TA 61 that a call is intended for him, after which the operator of the switch panel 765 returns the dialing key K 735 to idle, which disconnects the telephone. headset 767 of dicorde 766 and establishes a connection between the front and rear plugs P 748 and P 758 of dicorde 766, so as to establish a communication between the called subscriber station T 41 of the main office 40 and the call call original pel, which was previously answered at the 765 attendant switch panel using the P 748 front plug of dicorde 766.



   At the end of the established communication, when the subscriber of the called subscriber station T 41 of the main office 40 hangs up, the rear monitoring relay R 755 of the dicorde 766 is actuated again, so as to switch on the lamp again. L 757 rear monitoring to give the operator of the switch panel 765 an end of conversation signal.

   The operator of the switchboard 765 then removes the back file P 758 of the dichord 766 of the jack J 807, so as to cause the release of the

  <Desc / Clms Page number 144>

 o trunk switches 805, so that the line circuit 842 associated with the subscriber line 841, terminating at the subscriber station T 41 is activated and indicates the subscriber line 841 as free to the train of trunk switches 805 and to the train of urban switches 844 which have access to said line.



   CALL FROM THE OPERATION SWITCH PANEL
FROM MAIN OFFICE 40 AND FOR A POSITION
SUBSCRIBE FROM: OFFICE 50.



   It will firstly be assumed that the operator of the switchboard 765 of the main office 40 has answered a call using the front plug P 748 of the dicorde 766 and neoessing a routing to a requested subscriber station such as for example the station subscriber T 51 of the remote office 50. The operator inserts the rear plug P 758 of the dicorde 766 into a jack terminating a free junction circuit of the group comprising in particular the junction circuit 800.

   Assuming that the junction circuit 800 is free at this moment, as indicated by the extinction state of the occupancy lamp L 817 the operator of the switchboard 765 can insert the rear plug P 758 in the jack J 815 terminating the junction circuit 800 after placing the numbering key K 737 of the dicorde 766 in its rear position. when the rear plug P 758 is thus inserted into the jack J 815. the contacts 816 of said jack are closed and complete an obvious circuit for the excitation of the jack relay R 835 in the junction circuit 800. In operation, the Jack relay R 835 closes, at contacts 839, an obvious circuit for switching on the occupancy lamp L 817, indicating the busy condition of junction circuit 800 at this time.

   The R 835 jack relay closes, at contacts 836, a circuit passing through contacts 866 for the energization of the second call relay.

  <Desc / Clms Page number 145>

 R 870. On the other hand, when the rear plug P 758 is inserted into the jack J 815, the respective plug bodies of these components are in contact and close a circuit passing through the contacts 751 for the excitation of the circuit. The winding of the rear monitoring relay R 755 of the dicorde 766 in series with the upper winding of the plug relay R 820 in the junction circuit 800 and a multiple circuit with its upper winding. As a result, the plug relay R 820 of the junction circuit 800 works and the front monitoring relay R 755 of the dicorde 766 also works, since it is of the marginal type.

   While operating, the rear monitoring relay R 755 closes, at contacts 756, an obvious circuit for switching on the rear monitoring lamp L 757, indicating that the call in question has not yet been routed and has not yet been answered.



  On the other hand, while operating, the plug relay R 820 closes, at contacts 822 and 824, a bypass connection between the impulse contacts 762 of the call dial D 760 of the dicorde 766 and the winding of the switch relay. second call R 865.



  The branch circuit shown includes contacts 883 and 885 and coils 876 'and 877 of the RC 875 translator as well as contacts 822 and 824 and the tip and loop of the J 815 jack and the P 758 rear plug. leaves, while operating, the plug relay R 820 interrupts, at contacts 826, a normally closed termination circuit comprising contacts 892, capacitor 834 and resistor 833 in shunt on windings 875 'and 877' of translator RC 875, since the adjacent terminals of windings 876 'and 877' are connected to each other through capacitor 874 '. On the other hand, the plug relay R 820 closes, at the contacts 821, a circuit passing through the contacts 868 and 836 for the energization of the signal output relay R 830.

  <Desc / Clms Page number 146>

 



   In operation, the signal output relay R 830 closes at contacts 831 an obvious circuit for the application of a ground potential to the signal output conductor C 803, which causes the output relay to operate. signals R 897 from powerline carrier 894 from main office 40.

   When operating, the signal output relay R 897 closes contacts 898 included in the anode circuit of the associated transmission amplifier, so that the carrier signal at 24.55 kilocycles is transmitted through the anode circuit. Powerline carrier 894 on line 80 which connects main office 40 to remote office 50. Powerline carrier 994 at remote office 50 responds to the 24.55 kilocycles carrier signal transmitted to it over the line. 80 by causing the signal input relay R 995 to de-energize, so that the latter relay closes, at contacts 996, an obvious circuit for the application of an earth potential to the signal input conductor C 904 so as to cause the signal input relay R 920 to be energized in the junction circuit 900.



   While operating, the signal input relay R 920 closes, at contacts 923, a circuit passing through contacts 965 'for energizing the bonding relay R 930 and closes, at contacts 921, a bypass comprising contacts 965, the resistor 916, the windings 913 and 914 of the translator RC 910 and the contacts 963 and 968 in bypass on the line conductors C 1031 and C 1032 of the junction 1030 leading to the arrival selector 1036.

   While operating, the bonding relay R 930 closes, at contacts 934, an obvious circuit for the application of an earth potential to the control conductor C 1035 of the junction 1030 leading to the arrival selector 1036. This is then attacked and made sensitive to the first digit transmitted on junction 1030 resulting in

  <Desc / Clms Page number 147>

 to said selector, In addition, the bonding relay R 930 interrupts, at contacts 936, a normally closed circuit passing through contacts 951 'for the application of a battery potential via the relay winding driving R 935 to the control conductor C 1043 of the junction 1040 leading to the junction circuit 900 and closes, to the contacts 935,

   an obvious circuit for the application of a ground potential to the control conductor C 1043, which indicates that the junction 1040 and therefore the junction circuit 900 as occupied at the selectors of the seeker-selector junctions 1062 etc ... arranged to the various positions of interurban operators of the Strowger 1060 automatic trunk switchboard who have access to said junction and to said circuit.



   The operator of the switchboard 765 of the main office 40 then proceeds to the formation on her call dial of the first digit of the call number of the called subscriber station T 51 of the remote office 50. When the dialing disk of the call dial D 760 incorporated in the dicor- of 768 is moved away from its rest position, the set of shunt contacts 761 is closed and remains closed until said disc must return to its rest position , while the pulse spring set 762 is actuated and transmits the pulses to the digit under consideration exclusively during the return of the numbering disc to its home position.



  When the call dial D 760 dial disc is rotated out of its home position, closing the shunt contact set 761, a circuit including the X 737 dial key idle contacts is closed. for energizing the rear numbering relay R 750. When operating, the rear numbering relay R 750 interrupts, at contacts 751, the circuit previously drawn for

  <Desc / Clms Page number 148>

 energizing the winding of the rear monitoring relay R 755 in series with the upper and lower windings mounted in parallel with the plug relay R 820, so that said relay releases its armature.

   By releasing its armature, the rear monitoring relay R 755 of dicorde 766 interrupts, at contacts 756, the circuit previously traced for lighting the rear monitoring lamp 757, and by releasing its armature, the plug relay R 820 of the junction circuit 800, interrupts, at contacts 822 and 824, the previously traced bypass leading to the second call relay R 865. On the other hand, the plug relay R 820 closes, at contacts 826, the circuit. of termination previously drawn including capacitor 834 and resistor 833 in shunt on windings 876 'and 877' of the RC 875 trans- lator.

   In addition, the plug relay R 820 closes a variant branch circuit at contacts 823 and 825 comprising the tip and loop of the J 815 jack and the P 758 tail plug, as well as the key contacts. reverse switch K 735 at rest, the rear contacts of the dial key K 737 at work and the pulse contacts 762 of the call dial D 760 to keep the signal output relay energized. R 830 of the junction circuit 800 and interrupts, at contacts 821, the original circuit previously drawn which kept the signal output relay R 820 activated.

     However, since the branch circuit drawn above for energizing the winding of the signal output relay R 830 in the junction circuit 800 passes through the pulse contacts 762 of the built-in call dial D 760. in dichord 766, the pulses of the digit under consideration transmitted by the pulse contacts 762 of the call dial D 760 as a result of the return of the dialing disc to its idle position are transmitted.

  <Desc / Clms Page number 149>

 put on the branch circuit previously drawn to the signal output relay R 830, so that this relay operates correspondingly.

   At this time, the signal output relay R 830 transmits the pulses of the relevant digit on the signal output conductor C 803 to contacts 831, so that the signal output relay R 897 of the current equipment carrier 894 operates accordingly. More precisely, the signal output relay R 897 of the carrier equipment 894 retransmits, to contacts 898, the pulses of the digit in question, so that the carrier signal at 24.55 kilocyoles is interrupted following the impulses of this figure.



  In this way, the signal input relay R 995 of the power line carrier 994 functions correspondingly by re-transmitting, to the contacts 996, corresponding earth potential pulses on the input conductor. signal 0 904, which causes a corresponding operation of the signal input relay R 920 of the junction circuit 900.



   The dialing disk of the call dial D 760 incorporated in the dicorde 766 is first activated according to the first digit of the call number of the called subscriber station T 51 of the remote office 50 as indicated above. and, when the dial disc returns to its home position, the pulse contacts 762 of the call dial D 760 have completed the transmission of the pulses of the first digit indicated and the shunt springs 761 of the call dial D 760 are open and interrupt the previously drawn circuit which kept the rear dial relay R 750 actuated, so that the latter relay releases its armature a short time later since it is of the delayed release type.

   By releasing its armature, the rear numbering relay R 750 closes, at contacts 751

  <Desc / Clms Page number 150>

 the circuit previously drawn for the energization of the rear monitoring relay R 755 in the dicorde 765 and of the plug relay R 820 in the junction circuit 800.

   When operating again, the rear monitoring relay R 755 turns on the rear monitoring lamp L 757 again and, when operating again, the plug relay R 820 again closes, at contacts 821, the original circuit previously drawn. for keeping the signal output relay R 830 in the junction circuit 800 in the working position, which also keeps the signal output relay R 897 of the powerline carrier 894 in the working position rest the signal input relay R 995 of powerline carrier equipment 994 and in the working position the signal input relay R 920 of the junction circuit 900, as explained previously.

   In addition, when operating again, the plug relay R 820 interrupts, at contacts 826, the termination circuit comprising the capacitor 834 and the resistor 853 in shunt on the windings 876 'and 877' of the translator RC. 875, at contacts 823 and 825 the branch circuit traced above comprising the pulse contacts 762 of the call dial D 760 incorporated in the dichord 766 for energizing the winding of the signal output relay R 830 and it closes, at contacts 822 and 824, the bypass connection previously traced between the pulse contacts 762 of the call dial D 760 incorporated in the dichord 766 and the winding of the second call relay R 865.



   As discussed above, the signal input relay R 920 of the junction circuit 900 operates according to the pulses of the first digit formed on the call dial of the operator switch board 765 of the main office 40.



  Whenever the R 920 signal input relay releases

  <Desc / Clms Page number 151>

 its armature then attracts it again, it interrupts then closes, at contacts 923, the previously traced circuit which kept the bonding relay R 930 actuated, so that the latter relay is maintained in its working position during the passage of pulses, since it is of the delayed release type. On the other hand, each time the signal input relay R 920 releases its armature then attracts it again, it closes and then interrupts, at contacts 922, a circuit passing through contacts 932 for excitation of the signal. numbering relay R 940, so that this latter relay is energized and remains activated during the passage of the pulses, since it is of the delayed release type.

   While operating, the numbering relay R 940 interrupts, at contacts 941 a normally closed connection comprising the capacitor 915 between the adjacent terminals of the windings 913 and 914 of the RC 910 translator and closes, at the contacts 942, a circuit comprising the resistor 919 for shorting the winding 913 of the translator RC 910, which facilitates the passage of the pulses on the line conductors C 1031 and C 1032 of the junction 1030 which ends at the arrival selector 1036.

   Finally, each time the signal input relay R 920 releases its armature then attracts it again, it interrupts and then closes, at contacts 921, the bypass circuit previously drawn between the line conductors C 1031 and C 1032. junction 1030 which terminates at arrival selector 1036, so that the pulses of the digit in question are transmitted through junction 1030 to arrival selector 1036. arrival selector 1036 responds to the first digit received by the junction 1030 by selecting the junction bundle comprising in particular the junction 1037 which ends in the train of interurban switches 1038, then in this bundle, a free junction.

   For example, the arrival selector 1036

  <Desc / Clms Page number 152>

 can select the particular junction 1037 leading to the trunk switch train 1038.



     At the end of the first digit, the signal input relay R 920 of the junction circuit 900 is held in its working position, as explained previously, so that the numbering relay R 940 releases its armature a short time later. , since it is of the delayed release type. By releasing its armature, the numbering relay R 940 interrupts, at contacts 942, the previously traced circuit leaving by resistor 919 and ensuring the short-circuiting of the winding 913 of translator RO 910 and closes again. contacts 941, the original connection previously shown comprising capacitor 915 between adjacent terminals of windings 913 and 914 of RC translator 910.



   From the foregoing, it will be understood that the call dial D 760 incorporated in the dicorde 766 is actuated successively according to the different digits of the call number of the called subscriber station T 51 of the remote office 50.



  The indicated digits are transmitted from the call dial D 760 to the R 830 signal output relay of the junction circuit 800, retransmitted by the R 830 signal output relay to the R 897 signal output relay of the 'powerline carrier equipment 894, then through the signal output relay R 897 to the signal input relay R 995 of the power line carrier 994, through the signal input relay R 995 to the input relay signals R 920 from junction circuit 900 and finally retransmitted by the signal input relay R 920 to junction 1030.

   The first digit transmitted to trunk 1030 produces an operation of inbound selector 1036, so that trunk 1037 terminating in trunk switch train 1038 is selected as described.

  <Desc / Clms Page number 153>

 above. Subsequent digits transmitted over trunk 1030 are transmitted through inbound selector 1036 and trunk 1037 to inter-city switch train 1038, so that this operates by selecting subscriber line 1051 terminating at the called subscriber station T 51 of the remote office 50, and the train of trunk switches 1038 test the called subscriber station T 51 to determine whether it is free or busy.



   It will first of all be assumed that the subscriber station T 51 of the remote office RO is busy at this moment, this busy state being indicated by the line circuit 1052 individually associated with the subscriber line 1051 leading to said station. the interurban switch train 1038 then interrupts sixty times per minute the normal application of the earth potential to the earth conductor of junction 1037 and, therefore, through the arrival selector 1036, to the corresponding control conductor dant C 1034 from junction 1030.

   It will be noted here that the upper and lower windings of the response relay R 975 of the junction circuit 900 are normally energized, the latter relay, being of the differential type, not operating when its two windings are thus energized. excitation of the lower winding of the response relay R 975 goes through contacts 934 of the actuated bonding relay R 930 and through oontacts 963 'and 987, and the excitation circuit of the upper winding of the response relay R 975 passes through contacts 933 of the relay, bonding R 930 aotated by oontacts 986 and by the control conductor C 1054 normally earthed from junction 1030,

   this grounding is normally done in the inbound selector 1036 or in the trunk switch train 1038 while the call is being routed. At the moment,

  <Desc / Clms Page number 154>

 the earth potential is removed sixty times per minute in the interurban switch train 1038 of the control conductor C 1034 of the junction 1030, so that the upper winding of the response relay R 975 is de-energized sixty times per minute in causing corresponding excitation and de-excitation of the latter relay. the response relay R 975 operates whenever its upper winding is de-energized and releases its armature each time its upper winding is energized again, given that it is of the differential type.

   As a result, the response relay R 975 attracts its armature and then releases it sixty times per minute by retransmitting corresponding pulses, at contacts 979, to the signal output conductor R 903, so that the signal start relay R 997 of powerline carrier apparatus 994 operates in a corresponding fashion.

   Each time the R 997 signal start relay attracts its armature and then releases it, it closes then interrupts, at contacts 998, the anode circuit of the associated transmission amplifier, so that the powerline carrier equipment 994 transmits on line 80 sixty counts per minute of carrier signal at 15.95 kilocycles causing a corresponding operation of a signal input relay R 895 of the carrier current equipment 694 and retransmission, to contacts 896, of Sixty positive pulses per minute on the C 804 signal input conductor. The R 860 signal input relay of the junction circuit 800 operates in a corresponding way.

   Each time the R 860 signal input relay attracts its armature, then releases it, it closes and then interrupts, at contacts 862, an obvious circuit for energizing the R 850 bonding relay, so that the latter relay energizes and is kept actuated at this time, since it is of the delayed release type. By operating

  <Desc / Clms Page number 155>

 the bonding relay R 850 closes, at contacts 853, an obvious multiple circuit which keeps the occupancy lamp L 817 on so as to indicate the occupation condition of the junction circuit 800 observed at that moment.

   On the other hand, each time the R 860 signal input relay operates and then releases its armature, it interrupts and then closes, at contacts 861, the circuit previously drawn for the energization of the lower winding of the relay. of plug R 820 in multiple with its upper winding and in series with the winding of the rear monitoring relay R 755 so that the monitoring relay R 755 attracts its armature then releases it sixty times per minute by retransmitting to contacts 756, pulses corresponding to the L 757 rear monitoring lamp.

   The flickering of the rear surveillance lamp L 757 at a rate of sixty times per minute indicates to the operator of the switchboard 765 of the main office 40 that the communication intended for the called subscriber station T 5I of the remote office 50 cannot be obtained. at this time due to the occupation status of this position. The switchboard operator 765 then frees the devices by removing the rear P 758 plug from the jack 815 which terminates the junction circuit 800 in a manner which will be discussed later in more detail.



   Assuming on the other hand that the called subscriber station T 51 of the remote office 50 is free when the subscriber line 1051 terminating at said station is tested by the toll switch train 1038, the toll switch train 1038 maintains the application of the earth potential to the earth conductor of the junction.



  1037, so that the upper winding of the response relay R 975 of the junction circuit 900 is kept energized

  <Desc / Clms Page number 156>

 and that the latter relay remains in its rest position.



  On the other hand, the trunk switch train 1038 operates by applying a inrush current to the subscriber line 1051 which terminates at the called subscriber station T 5I and returning a calling party warning tone current to the caller. call of the called party on junction 1037 and from there, through the arrival selector 1038, on the line conductors C 1031 and C 1032 of junction 1030 and on the previously traced circuit comprising the windings 913 and 914 of the RC translator 910. The return tone current flowing through the windings 913 and 914 of the RC translator 910 induces an audible tone current back into the windings 911 and 912 of said translator, which current is transmitted through the line conductors C 901 and C 902 to powerline carrier equipment 994.

   The balanced modulator of the carrier current apparatus 994 modulates the carrier signal at 15.95 kilocycles following the return tone current and transmits the carrier signal at 15.95 kilocycles modulated on line 80 to the apparatus for current carrier 894, so that the balanced demodulator of carrier current equipment 894 demodulates the modulated 15.95 kilocycles carrier signal and transmits its modulator component to the C 801 and C 802 line conductors.

   In this manner, the audible return tone current passes through the coils 878 'and 879' of the RC translator 875 inducing a corresponding return tone current in the coils 876 'and 877' of said transformer. This current is returned by the circuit previously drawn to the headset 767 of the requesting operator switchboard 765 of the main office 40 assuming that the rear talk key K 735 is activated at this time, so as to indicate to the operator of said table that the called subscriber station T 51 of the remote office 50 is called.

  <Desc / Clms Page number 157>

 



   When the subscriber of the called station T 51 of the remote office 50 answers the call, the train of inter-city switches 1038 interrupts the application of the earth potential to the earth conductor of the junction 1037, so that the potential earth is removed from the control conductor C 1034 of junction 1030 by de-energizing the upper winding of response relay R 975, the latter relay then operating as explained previously. On the other hand, trunk switch traLn 1038 operates by interrupting the return of tone current back to the circuit previously drawn to operator switch board 765 at main office 40.

   In operation, the response relay R 975 of the junction circuit 900 closes at contacts 979, an obvious circuit for the application of a ground potential to the signal output conductor C 903 by causing the output relay to operate if - signals R 997 of the carrier current equipment 994, so that the carrier signal at 15.95 kilocles is transmitted through line 80 causing the de-energization of the signal input relay R 895 of the carrier current equipment 894 and the corresponding operation of the signal input relay R 860 of the junction circuit 800, all in the manner previously explained.

   When operating, the R 860 signal input relay causes the R 850 bonding relay to operate and interrupts, at contacts 861, the circuit previously drawn for the energization of the lower winding of the R 820 plug relay in parallel with its upper winding and in series with the winding of the rear monitoring relay R 755, so that the plug relay R 820 of the junction circuit 800 is kept in its working position) and the rear surveillance R 755 of the dicorde 766 releases its frame.

   By releasing its armature, the rear monitoring relay R 755 interrupts, at contacts 756, the circuit previously traced for ignition.

  <Desc / Clms Page number 158>

 of the rear surveillance lamp L 757, which indicates to the operator of the switchboard 765 of the main office 40 that the call has been ob j and of a response from the called subscriber station T 51 from remote office 50.

   In time, the operator of the switchboard 765 notifies the subscriber of the requested set T 51 that a call is intended for him. The operator of the switch panel 765 then returns the rear conversation key K 735 to the rest position, interrupting the connection with the 767 headset and establishing the previously indicated connection between the front and rear plugs P748 and P 758 in such a way. a establish a communication between the circuit arriving at the main office 40 on which the call was previously answered and the subscriber of the called station T 51 of the remote office 50.



   At this moment, an acoustic signal originating in the incoming circuit passes through the dichord 766, the Jack J 815 and the windings 876 'and 877' of the translator RC 875 by inducing a corresponding signal in the windings 878 'and 879' of said translator. said signal is transmitted on the line connectors C 801 and C 802 to the carrier current equipment 894 so that the balanced modulator of the carrier current equipment 894 modulates the carrier signal at 24.55 kilocycles in a corresponding manner and that the balanced demodulator of the carrier current apparatus 994 demodulates the modulated carrier signal at 24,

  55 kilocycles received and transmits its acoustic component on the line conductors C 901 and C 902 to the windings 911 and 912 of the transla- tor RC 910 by causing the induction of a corresponding signal in the windings 913 and 914 of said t ransl at eur. This acoustic signal is transmitted by the previously traced connection comprising the junction 1030, the arrival selector 1036, the junction 1037, the train of long distance switches 1038 and the subscriber line I05I to the called subscriber station T 51

  <Desc / Clms Page number 159>

 from the remote office 50.



   Similarly, an acoustic signal originating at the called subscriber station T 51 crosses the previously traced connection comprising the subscriber line 1051 the long distance switch train 1038, the junction 1037 the arrival selector 1036 , junction 1030 and windings 913 and 914 of the RC 910 transformer by inducing a corresponding signal in the windings 911 and 912 of said transformer, and this signal is transmitted through the line conductors C 901 and C 902 to the load-bearing sewing device 994.

   The balanced carrier demodulator 994 responds by modulating the carrier signal at 15.95 kilocycles and transmitting said modulated carrier signal at 15.95 kilocycles on line 90, so that the balanced demodulator of the carrier equipment carrier current 894 reacts and demodulates the received 15.95 kilocycles modulated carrier signal, transmitting its acoustic component over line conductors C 801 and C 802 to windings 878 'and 879' of the RC 875 translator. The corresponding acoustic signal is then induced in windings 876 'and 877' of the RC 875 translator and passes through the previously traced connection comprising the J jack 815 and the dichord 766 to lead to the arrival circuit of the main office 40.



   Considering again the operation of the trunk switch train 1038, it will be noted that this apparatus responds to several digits by causing the selection of the subscriber line 1051 resulting in the requested subscriber station T 51 of the remote office 50. Consequently, this apparatus naturally comprises a number of the corresponding switching stages. As a result, any given switching stage of trunk switch train 1038 may find all subsequent stages occupied. Under these conditions, it interrupts one hundred and twenty times per minute the application of an earth potential to the earth conductor of junction 1037

  <Desc / Clms Page number 160>

 and, consequently, to the control conductor C 1034 of the junction 1030.

   The response relay R 975 then operates in a corresponding way. When the response relay R 975 of the junction circuit 900 operates at a rate of one hundred and twenty pulses per minute, it retransmits these pulses to the contacts 979 of the power line switchgear 994 which retransmits them to the power line switchgear 894, which transmits them. transmits in turn to the signal input relay R 860 of the junction circuit 800. all in the manner described above.



   Thus, the signal input relay R 860, by pulling and releasing its armature one hundred and twenty times per minute, causes a corresponding de-energization and re-energization of the rear monitoring relay R 765 in the dicorde 766, so that the rear monitoring lamp L 757 is switched on intermittently at a rate of 120 times per minute.

   This flickering of the rear monitoring lamp L 757 at a rate of 120 times per minute indicates to the operator of switchboard 765 in main office 40 that an interurban switching stage of interurban switch train 1038 has been found. in the presence of a condition of full occupancy and the current call cannot be routed at that time to remote office 50 because of this condition.



   From the foregoing, it will be understood that the arrival selector 1036 is sensitive to a condition of total occupation of the junction bundle comprising the junction 1037 in an identical manner by interrupting the application of the potential one hundred and twenty times per minute. earth to the control conductor C 1034 of junction 1030, so as to cause a corresponding flickering of the rear monitoring lamp L 757 of the requesting switchboard 765 of the main office 40

  <Desc / Clms Page number 161>

 at the end of the first digit formed on the call dial as a result of the full occupancy condition encountered.



   Accordingly, it will be understood that at the end of each digit formed on the call dial of the calling operator switch panel 765 of the main office 40, the rear monitoring lamp L 757 is steadily turned on in the event that the last interurban switching stage operated at the remote office 50 has found a free output line, while the lamp (the rear surveillance L 757 is switched on and off intermittently at the rate of one hundred and twenty times per minute in the event that the last stage of Trunk switch actuated is in the presence of a full occupancy condition as discussed above.

   Finally, in the case where the subscriber line terminating at the subscriber station T 51 is occupied during the test carried out by the last interurban switching stage of the train of interurban switches 1038, said stage operates in an identical manner in causing the rear watch lamp] 757 to flicker at sixty times per minute, as discussed above.

   The flickering of the rear watchdog lamp at the rate of eent twenty times per minute indicates a full occupancy condition while its flickering at the rate of sixty times per minute indicates a condition of occupation of the called subscriber station T 51 from the distant office 50
On the other hand, with regard to the operation of the trunk switching stages of the remote office 50, it will be observed that a predetermined trunk switching stage may be of the multi-level seeker type, so that considerable time is required afterwards. receipt of a digit before the trunk switching floor in question can determine whether all available output lines are busy.

   In this case, the switching stage

  <Desc / Clms Page number 162>

 pre-determined intercity interrupts the application of a ground potential to the earth conductor of junction 1037 during its multi-level selection operation so that the earth potential is removed from the control conductor C 1034 of junction 1030 by causing the response relay R 975 of the junction circuit 900 to operate.

   Then, when the predetermined trunk switching stage completes its multi-level selection operation and finds a free output line, it again applies an earth potential to the earth conductor of junction 1037 and hence to the control conductor C 1034 of junction 1030, which causes de-energization of the response relay R 975.

   Accordingly, during the multi-level selection operation of the trunk switching step of the trunk switch train 1038, the response relay R 975 of the trunk circuit 900 is actuated by causing the signal output relay to be energized. R 997 of powerline carrier equipment 994, a corresponding de-energization of the signal input relay R 895 of the powerline carrier 894 and a corresponding energization of the signal input relay R 860 of the junction circuit 800. The input relay R 860 signals activated causes the de-energization of the rear monitoring relay R 755 of the dicoree 766, all in the manner explained previously.

   As a result, the rear monitoring relay R 755 of dicorde 766 remains de-energized during the multi-level selection operation of the predetermined trunk switching stage of trunk switch train 1038 of remote office 50, so that the L 757 rear surveillance light remains off after training on the last digit call dial by the operator of the requesting switchboard 765 in the main office 40.

   The

  <Desc / Clms Page number 163>

 condition of extinction of the rear surveillance lamp L 757 after training on the call dial by the operator of the requesting switch panel 765 of the last digit indicates to the operator of said panel that a step this predetermined interurban switching of long distance switch train 1038 of remote office 50 at this time performs a selection operation on several levels and warns him not to form on his dial the next digit before this operation is completed on the switching floor long distance indicated, which is evidenced by the new illumination of the L 757 rear monitoring lamp.

   When the rear surveillance lamp L 757 is switched on again, the operator of the calling switch panel 765 is switched on again, the operator of the calling switch panel 765 of the main office 40 carries out training on his call dial. the next digit of the call number of the called subscriber station T 51 of the remote office 50.



   From what precedes, we will realize that the operator of the requesting switchboard 765 of the main office 40 must wait for the new lighting of the rear surveillance lamp L 757 after the formation on the call dial of each digit of the call number of the requested subscriber station T 51 and before the next digit of said call number is formed.



   Finally, it will be noted that during the communication established between the arrival circuit of the main office 40 and the called subscriber station T 51 of the remote office 50, the subscriber of the called station T 51 has a possibility of control by means of the hook of his apparatus and can attract the attention of the operator of the switchboard 765 of the main office 40 by operating the said hook intermittently.

  <Desc / Clms Page number 164>

 



  The trunk switch train 1038 is controlled in a corresponding manner by reapplying a ground potential to the ground conductor of junction 1037 and interrupting the application of said ground potential. Consequently, an earth potential is applied to the control conductor C 1034 of the junction 1030 and then eliminated from said conductor, causing a de-energization and then a re-energization of the response relay R 975 of the junction circuit 900.



  The signal output relay R 997 is then de-energized and then re-energized correspondingly, causing a re-energization and then a corresponding de-energization of the signal input relay R 895 of the powerline carrier 894. The relay of signal input R 860 from the junction circuit
800 tion is then de-energized then re-energized in the same way and itself causes an energization and then de-energization of the rear monitoring relay R 755 of the dicorde 766. The rear monitoring lamp L 757 is switched on and off in a corresponding manner.

   Thus, the manipulation of the hook switch of the called subscriber station T 51 of the remote office 50 causes a corresponding flickering of the rear monitoring lamp L 757 of the requesting switch board 765 of the main office 40, which indicates to the operator that the subscriber of the called set T 51 wishes to speak to him.



   The operator of the switchboard 765 can re-enter listening by activating the rear conversation key K 735, which again connects the headset 767 to the rear connector P 758 of the dicorde 766. At this time, the The subscriber of the called station T 51 of the remote office 50 can indicate to the operator of the requesting switchboard 765 of the main office 40 what he wishes.



   At the end of the established communication, when the subscriber of the called set T 51 of the remote office 50 hangs up, the

  <Desc / Clms Page number 165>

 interurban switch train 103.8 again applies an earth potential to the earth conductor of junction 1037, so that an earth potential is reapplied to the control conductor C 1034 of junction 1030, causing de-excitation of the response relay R 975 of the junction circuit 900. By releasing its armature, the response relay R 975 causes the de-energization of the signal output relay R 997 of the power line carrier 994 and consequently the switch-off. re-energization of signal input relay R 895 of powerline carrier equipment 894.

   The signal input relay R 860 of the junction circuit 800 is then de-energized and the rear monitoring relay R 755 of the dicorde 766 is re-energized by switching on the rear monitoring lamp, L 757, which indicates to the panel operator. switch 765 of the main office 40 which the station subscriber requests T 51 of the remote office 50 has hung up.



   At this moment, on receiving the end of conversation signal, the operator at switchboard 765 of the main office 40 cuts off communication with the called subscriber station T 51 of the remote office 50 by removing the rear plug P 758 of the R 815 jack which terminates the 800 junction circuit which interrupts the circuits which kept the R 820 plug relay and the R 835 jack relay of the 800 junction circuit energized, so that the latter relay releases its armature a short instant later since it is of the delayed release type.

   By releasing its armature, the plug relay R 820 interrupts, at contacts 821, the circuit previously drawn which kept the relay actuated for a sort of signals R 830 and closes, at contacts 826, the termination circuit comprising capacitor 834 and resistor 833 in shunt on windings 876 'and 877' of the RC 875 translator. By releasing its armature, the relay

  <Desc / Clms Page number 166>

 of jack R 835 interrupts, at coitus acts 836, the previously drawn circuit which kept the second call relay R 870 actuated, so that the latter relay releases its armature a short time later, since it is delayed release type.

   By releasing its armature, the signal output relay R 830 interrupts, at contacts 831, the circuit previously drawn for the application of an earth potential to the signal output conductor C 803 so as to cause the relay to de-energize. signal output R 897 from powerline carrier equipment 894 and consequently re-energizing the input relay, signals R 995 from power line carrier 994, so that the signal input relay R 920 of the junction circuit 900 releases its armature,
By releasing its armature, the signal input relay R 920 interrupts, at contacts 923, the circuit previously drawn for the excitation of the bonding relay R 930 in such a way that the latter relay releases its armature for a short time. late since it is the delayed release type.

   By releasing its armature, the bonding relay R 930 interrupts, at contacts 935, the circuit previously drawn for the application of an earth potential to the control conductor C 1043 of junction 1040, and closes again at contacts 936, the circuit previously drawn for the application of a battery potential via the winding of the driving relay R 955 to the control conductor C 1043. which indicates that the junction 1040 as free to the junction selectors selector finder 1062 etc ... arranged in the various interurban operating positions of the Strowger 1060 automatic interurban switchboard which has access to said junction.

   In addition, the bonding relay R 930 interrupts, at contacts 933 and 934, points of the circuits previously traced for the excitation of the upper and lower windings of the response relay R 975, so that

  <Desc / Clms Page number 167>

 the latter relay remains in its rest position. Finally, the bonding relay R 930 interrupts, at contacts 934, the circuit previously drawn for the application of an earth potential to the control conductor C 1035 of the junction 1030, which causes the release of the train of interurban switches 1038 and the arrival selector 1036.

   At this time, the line circuit 1052 associated with the subscriber line 1051 which terminates at the subscriber station T 51 indicates the subscriber line 1051 as free to the inter-office switch train 1038 and to the switch train. urban 1054 who have access to said line.



   At this moment, the communication established between the requesting switchboard 765 of the main office 40 and the called subscriber station T 51 of the remote exchange 50 is interrupted and all the apparatuses interested in said communication are completely released and become available for a call. subsequent use.



   URBAN CALLS TO REMOTE OFFICE 50 - ---------------------------------
First of all, it will be assumed that a call initiated by a subscriber station such as, for example, the T 51 station of the remote office 50 must be routed to another subscriber station of said office. when the call is initiated at the calling subscriber station T 51, the line circuit 1052 associated with the subscriber line 1051 indicates the subscriber line 1051 as busy to the urban switch train 1054 and to the switch train trunk 1038 who have access to said line and trigger a free part of the train of city switches 1054 and the finder of this part is working by attacking the subscriber line 1051.

   The subscriber of the calling station T 51 then forms the call number of the called subscriber station on his dial, so that the different: s selectors then

  <Desc / Clms Page number 168>

 the connector for the 1054 city switch train is working. The indicated connector selects, in operation, the subscriber line terminating at the requested subscriber station.



  At this moment, said connector tests the requested subscriber set to determine whether it is free or busy. The routing and final termination of the communication established between the calling subscriber station T 51 and the called subscriber station of the remote office 50 is in accordance with the usual practice.



   CALL FROM A SUBSCRIBER AND DESTINATION
TO THE AUTOMATIC STROWGER INTER-URBAN PANEL
REMOTE OFFICE 50
It will first of all be assumed that a call initiated by a subscriber station, such as for example the subscriber station T 51 of the remote office 50, must be routed to the Stowger automatic toll table 1060 of said office. On the other hand, it will be assumed that the train of city switches 1054 has attacked the line 1051 which ends at the calling subscriber set T 51. The subscriber of the calling subscriber set T 51 then forms the single digit on his dial. designated as the call number of the Strowger 1060 automatic long distance table to the remote office 50, a single digit which can be for example "0".

   City switch train 1054 responds to the single digit "0" by selecting the trunk bundle including trunk 1055, and then, in that trunk, a free trunk. For example, the train of city switches 1054 may previously select junction 1055 which terminates at direct traffic junction 1056. Direct traffic junction 1056 then operates by applying a call to output junction 1057 which originates from said junction. - direct traffic stop and by triggering the operation of the distribution devices included in the Strowger 1060 automatic interurban switchboard.

   The call is then the object

  <Desc / Clms Page number 169>

 a response by one of the free interurban operator positions, such as for example the interurban operator position 1061, and the operation of a free searcher-selector junction individually associated with the position long distance operator 1061, such as for example the searcher junction selector 1062. More precisely, the searcher of said junction 1062 selects the output junction 1057 starting from the direct traffic junction 1056 said junction 1062 being connected at this time to the interurban operator position 1061,

     so that a communication is established between the calling subscriber station T 51 and the long distance operator position 1061 of the tabla to the called Strowger automatic long distance 1060 of the remote office 50. The subscriber of the calling station T 51 of the office remote 50 gives the operator of the trunk position 1061 of the automatic trunk table 1060 the information relating to the routing of the call, so that said operator routes the call using the selector of the searcher-selector junction 1062 at this time in service, the control being exercised by the keyboard associated with the recorder-transmitter of the long distance operator position 1061 of the automatic long distance switchboard 1060 according to the usual practice.



   At the end of the established communication, when the subscriber of the calling station T 51 of the remote office 50 hangs up, the direct traffic junction 1056 applies an earth potential to the earth conductor of the junction 1057 by switching on the monitoring door. back of the interurban operator position 1061 associated with the searcher of the searcher-selector junction 1062, so as to indicate to the operator of the interurban position 1061 of the automatic toll panel 1060 that the subscriber of the calling set T 51 included in communications routed through the searcher of the

  <Desc / Clms Page number 170>

 junction finder selector I062.a hung up.

   The operator of the long distance position 1061 of the automatic long distance table 1060 then activates the junction release key associated with the selector searcher junction 1062, so as to cause the release of said junction. In this way, the junction 1057 starting from the direct traffic junction 1056 is released, causing the freeing of the direct traffic junction 1056 and, therefore, the train of city switches 1054. The line circuit 1052 then operates in indicating that the subscriber line 1051 terminating at the subscriber station T 51 is free at the train of city switches 1054 and at the train of trunk switches 1038.



   CALL FROM THE AUTOMATIC INTER-URBAN PANEL
STROWGER AND DESTINATION TO A SUBSCRIBER OF THE OFFICE
FAR 50.



   It will first be assumed that the operator of one of the trunk positions, such as for example position 1061 of the Strowger 1060 automatic trunk switchboard of remote office 50, has answered a call using the finder of a finder junction. free selector individually associated with said position, such as, for example, the searcher-selector junction 1062, the call having to be routed to a requested subscriber station, such as for example the T 51 station. the long distance position 1061 of the automatic long distance table 1060 then actuates the associated keyboard, so that the transmitter recorder in service operates by transmitting a corresponding number of digits.

   The first digit transmitted by the transmitting recorder produces the operation of the finder-selector junction selector 1062 which selects the bundle of junctions including the junction 1037 terminating in the train of trunk switches 1038 and then in that bundle. a free junction.

   For example, the selector of the junction

  <Desc / Clms Page number 171>

 finder-selector 1062 can select the particular junction 1037 terminating in trunk switch train 1038. The other digits transmitted by the transceiver recorder are transmitted through the selector of the finder-selector junction 1062 and by the intermediary of the junction 1037 to the train of trunk switches 1038, so that the latter selects the subscriber line 1051 terminating at the requested subscriber station T 51.

   At this time, the active sender recorder is released and the trunk switch train 1038 tests the T subscriber station 51 to determine whether it is free or busy.



  Assuming that the called subscriber station T 51 is free, inrush current is applied from the trunk switch train 1038 on the subscriber line 1051 which terminates at said station. On the other hand, the front monitoring lamp of the long distance attendant position 1061 associated with the selector of the searcher-selector junction 1062 is on, which indicates that the call has not yet been submitted. 'a response from the requested subscriber station T 51.



  When the subscriber of the called station T 51 answers the call, a connection is established between the operator station of the trunk position 1061 of the automatic trunk table 1060 and the called subscriber station T 51, and the lamp. front watchdog indicated is off, which indicates to the operator of trunk position 1061 of the automatic trunk panel I060 that the call routed through the selector of the searcher-selector junction 1062 to the called subscriber station 1 ... ±! received a response.



  The operator of the long distance position 1061 of the automatic long distance table 1060 then notifies the subscriber of the called set T 51 that a call is intended for him, after which the operator of the long distance position 1061 withdraws from the telephone line.

  <Desc / Clms Page number 172>

 of the line by disconnecting the searcher-selector trunk 1062. A communication is then established between the original call which was previously answered at the long distance operator position 1061, using the searcher on the line. searcher-selector junction 1062 and the called subscriber set T 51 of the remote office 50.



   At the end of the established communication, when the subscriber of the called set T 51 of the remote office 50 hangs up, the front surveillance lamp of the long distance attendant position 1061 associated with the selector of the searcher-selector junction 1062 is on again, which gives an end of conversation signal to the long distance operator position 1061 to the automatic long distance switchboard 1060, after which the operator of the long distance position 1061 activates the junction release key associated with the searcher junction -selector 1062, so as to release the latter and, consequently, the train of interurban switches 1038.

   On this release, the line circuit 1052 again indicates the subscriber line 1051 terminating at the subscriber station T 51 as being free to the train of city switches 1054 and to the train of trunk switches 1038 which have access to said train. line.



   CALL FROM THE AUTOMATIC STROWGER INTER-URBAN PANEL OF THE REMOTE OFFICE 50 TO A SUBSTATION
 EMI172.1
 I1 BONNE DU BUREAU BRINCI2 at% 40.



   It will first be assumed that the operator of a long distance position, for example position 1061 of the Strowger automatic long distance table 1060 of remote office 50, has answered a call using the finder of a seeker junction. selector associated individually with said position, for example the selector finder junction

  <Desc / Clms Page number 173>

   1062, and requiring routing to a requested subscriber station, for example the T 41 station of the main office 40.



  The operator of the long distance position 1061 activates the associated keypad and the recorder-transmitter in service transmits a certain number of corresponding digits. The first digit transmitted by the indicated transmitter recorder causes the operation of the selector switch of the selector finder junction 1062 which selects the junction bundle comprising the junction 1040 and then, in this bundle, a free junction.



  For example, the selector of the finder-selector junction 1062 can precisely select the junction 1040 leading to the junction circuit 900, the junction 1040 being indicated as free by the presence of a battery potential on its control conductor C 1043, by the intermediary of a normally closed circuit passing through contacts 936 and 951 'and through the winding of the drive relay R 955 of the junction circuit 900. When the selector of the searcher-selector junction 1062 drives the junction 1040 at this moment the earth potential of the finder-selector junction is applied to the control conductor C 1043 of the 1040 junction by closing a circuit substantially identical to that previously drawn for the excitation of the R 955 drive relay in the circuit junction 900.

   While operating, the drive relay R 955 closes, at contacts 956, an obvious circuit for the energization of the switching relay R 960 and a circuit in parallel also comprising the contacts 971 for the energization of the second call relay R 1025 When operating, the switching relay R 960 interrupts, at contacts 961, the original termination circuit previously drawn comprising the capacitor 917 and the resistor 918 in shunt on the line conductors C 901 and C 902 which

  <Desc / Clms Page number 174>

 terminate at powerline carrier 994 and close, at contacts 962, an additional termination circuit comprising contacts 981 and 951, capacitor 917 and resistor 918 in shunt on the line conductors C 901 and C 902 indicated.

   On the other hand, the switching relay R 960 interrupts, at contacts 963 and 968, the normal connection between the line conductors C 1031 and C 1032 of the junction 1030 leading to the arrival selector 1036 and the windings 913 and 914 of the translator RC 910 and closes at contacts 964, 966, 967 and 969, a loop circuit between line relay R 1010 of junction circuit 900 and the transmitter of the indicated recorder-transmitter connected at this time to the searcher junction - selector 1062.

   The loop circuit in question is established as follows: earth, upper winding of line relay R 1010, contacts 984 and 967, winding 914 of translator RC 910, contacts 969, line conductor C 1042 and battery, lower winding of line relay R 1010, contacts 982 and 966, winding 913 of the translator RC 910, contacts 964, line conductor C 1041, the line conductors C 1041 and C 1042 of junction 1040 being at this moment connected by the intermediary of the selector of the finder-selector junction 1062, to the transmitter of the indicated transmitter recorder, Consequently, the upper and lower windings of the line relay R 1010 are energized at this moment by the loop circuit traced below - above leading to the transmitter of the recorder-transmitter,

     so that the last relay indicated operates. On the other hand, the switching relay R 960 closes, at contacts 961, a circuit comprising the contacts 922, 931, 944 and 986 for the excitation of the upper winding of the response relay R 975 and closes, at contacts 964 ', a circuit comprising contacts 987 for energizing the lower winding of the response relay

  <Desc / Clms Page number 175>

 R 975. When the upper and lower windings of the R 975 response relay are both energized in this way, the latter relay does not operate since it is of the differential type.



   While operating, the line relay R 1010 closes, at contacts 1012, a circuit passing through contacts 984 'for the application of an earth potential to the signal output conductor C 903, which causes the operation of the signal relay. R 997 signal output from powerline carrier equipment 994.

   When operating, the signal output relay R 997 closes the contacts 998 included in the anode circuit of 1 associated transmission amplifier, so that the carrier signal at 15.95 kilocycles is transmitted on line 80, so as to bring the de-energization of the signal input relay R 895 of the power line carrier 894, so that this last relay closes, at the contacts 896, the circuit previously traced for the application of an earth potential to the conductor input signals C 804, so as to cause the energization of the input relay @ signal. ,,, R 860 of the junction circuit 800.

   While operating, the signal input relay R 860 closes, at contacts 862, an obvious circuit for energizing the R 850 bonding relay, this latter relay closes at contacts 853, an obvious circuit for switching on the occupation lanpe L 817, so as to indicate the occupation condition of the junction circuit 800 to the operator of the switchboard 765 of the main office 40. In addition, the bonding relay 850 closes at contacts 851 , an obvious circuit for the energization of the right winding of the response relay R 890 and closes, at the contacts 852 a circuit passing through the contacts 838 for the energization of the switching relay R 880.

   When operating, the switching relay R 880 interrupts, at contacts 883 and 885, the normal connection between the winding of the second call relay R 865 and the windings 876 'and 877' of the translator.

  <Desc / Clms Page number 176>

 RC 875 and closes, at contacts 881, 884, 886 and 887, a loop circuit between the left winding of the response relay R 890 and line conductors C 886 and C 887 of junction 875 which ends at the selector arrival 812.

   More precisely, the line conductor C 876 of the junction 875 is connected by the intermediary of the contacts 881 of the winding 876 'of the translator RC 875, the contacts 884, of the left winding of the response relay R 890, from contacts 886, from the winding 8771 of the translator RC 875 and from the contacts 863 and 887, to the line conductor C 877 of the junction 875, so that the left winding of the relay response R 890 is excited on the circuit plotted above but is not biased, so it attracts its armature.

   Finally, the switching relay R 880, at contacts 888, closes an obvious circuit for the application of an earth potential to the control conductor C 878 of junction 875, so as to trigger the attack of the selector d. arrival 812, after which arrival selector 812 is made responsive to the first digit transmitted on junction 875.



   When the transmitter of the transmitter recorder in service transmits the following digit on the selector of the finder-selector junction 1062 at junction 1040, the line relay R 1010 of the junction circuit 900 operates correspondingly. Each time the line relay R 1010 releases its armature, then attracts it again, it closes, then interrupts, at contacts IOII, a circuit passing through contacts 982 'and 962' for excitation of the numbering relay R 940, so that the latter relay operates and remains actuated during the passage of the pulses, since it is of the delayed release type.

   When operating the numbering relay R 940 interrupts, at contacts 941

  <Desc / Clms Page number 177>

 the connection normally established comprising the capacitor 915 between the adjacent terminals of the windings 913 and 914 of the translator RC 910 and closes, at the contacts 942 the circuit previously drawn comprising the resistor 919 at the terminals of the winding 913 of the translator RC 910, so as to reduce the impedence of the loop circuit connecting line relay R 1010 of junction circuit 900 to the transmitter of the recorder-transmitter in use at this time.

   On the other hand, the numbering relay R 940 closes, at contacts 943, a variant circuit passing through contacts 961 'and 986 for the excitation of the upper winding of the response relay R 975 and interrupts, at contacts 944, the original circuit previously drawn for the excitation of the upper winding of the response relay R 975.

   In addition, each time the line relay R 100 releases its armature and then attracts it again, it interrupts and then closes, at contacts 1012, the circuit previously drawn for the application of an earth potential to the output conductor of signals C 903 and the signal output relay R 997 of the powerline carrier 994 operates according to the pulses of the digit in question by retransmitting said pulses to the contacts 998, so that the signal input relay R 895 of the Powerline carrier 894 works the same way.

   Each time the signal input relay R 895 attracts its armature then releases it, it interrupts, then closes, at contacts 896, the circuit previously traced for the application of an earth potential to the conductor d. C signal input 804, so that the signal input relay R 860 of the junction circuit 800 operates in a corresponding manner.

   Each time the R 860 signal input relay releases its armature and then attracts it again, it closes and then interrupts, at contacts 861, a circuit passing through the contacts.

  <Desc / Clms Page number 178>

 tacts 882 for energizing the numbering relay R 855 so that the latter relay is energized and remains actuated during the passage of the pulses, given that it is of the delayed release type. While operating, the numbering relay R 855 closes, at contacts 856, a circuit passing through contacts 884, resistor 832 and contacts 881 for short-circuiting the winding: 876 of the RC 875 translator, this which facilitates the transmission of the pulses on the line conductors C 876 and C 877 of the junction 875 which leads to the arrival selector 812.

   Finally, each time the R 860 signal input relay releases its armature, then attracts it again, it interrupts, then closes, at contacts 863, the bypass circuit previously drawn between the left winding of the response relay R 890 and the incoming selector 812, via the line conductors C 876 and C 877 of junction 875. The signal input relay R 860 then transmits the pulses to contacts 863 of the number being transmitted on junction 875, and from there to the arrival selector 812. The arrival selector 812 is actuated according to the considered digit and selects the trunk bundle comprising the junction 806 then, in this bundle, a free junction.

   For example, inbound selector 812 may precisely select trunk 805 which terminates in interurban switch train 805, so that trunk-switch train 805 is packaged in such a way that it is responsive to other digits transmitted over it. junction 875.



   At the end of the figure considered, the line relay R 1010 of the junction circuit 900 is maintained in its working position and maintains interrupted, at contacts IOII, the circuit previously drawn which kept the relay actuated.

  <Desc / Clms Page number 179>

 numbering R 940, so that the latter relay releases its armature a short time later since it is of the delayed release type.

   By releasing its armature, the numbering relay R 940 interrupts, at contacts 942, the circuit passing through resistor 919 and short-circuits the winding 913 of translator RC 910 and closes, at contacts 941, the conne :. previously traced normal ion passing through capacitor 915 between the adjacent terminals of windings 913 and 914 of RC translator 910.



  On the other hand, the numbering relay R 940 closes, at contacts 944, the original circuit previously drawn for the excitation, of the upper winding of the response relay R 975 and interrupts, at contacts 943, the previously variant circuit. trace for the excitation of the upper winding of the response relay R 975. In addition, at the end of the transmission of the considered digit, the signal input relay R 860 of the junction circuit 800 remains in its position. working ion while maintaining interrupted, at contacts 861, the previously drawn circuit which kept the numbering relay R 855 actuated and this last relay releases its armature a short instant later, given that it is of the release type. deferred.

   By releasing its armature, the numbering relay R 855 interrupts, at contacts 856, the previously drawn circuit passing through resistor 832 which short-circuits the winding 876 'of the RC 875 transformer.



   From the foregoing, it will be understood that the other digits recorded in the recorder-transmitter in service are transmitted by, the latter through the selector of the searcher junction selector 1062 and of the junction 1040 to the line relay R 1010 of the junction circuit 900 in an identical manner ,. the figures indicated are retransmitted

  <Desc / Clms Page number 180>

 via the line relay R 1010 to the signal output relay R 997 of the powerline carrier 994 and, consequently, to the signal input relay R 895 of the powerline carrier 894.

   the indicated digits are then retransmitted to the signal input relay R 860 of the junction circuit 800 and the signal input relay R 860 transmits them, to the contacts 863, through the junction 875, the incoming selector 812 and junction 806 to trunk switches 805, all in an identical manner to that previously discussed. As a result, trunk switch train 805 responds to the indicated digit by selecting subscriber line 841 which terminates at called subscriber station T 41 at main office 40. trunk switch 805 then tests station d. 'subscriber T 41 to determine whether he is free or busy at this time, following the usual practice.



   After the transmission by the recorder-transmitter in service of the last digit recorded in this apparatus on junction 1040 to line relay R 1010 of the junction circuit 900 in the manner described above, said recorder-transmitter applies, by through the selector of the finder-selector junction 1062, a battery potential on the control conductor C 1042 of the junction.



  1040, which closes a circuit passing through contacts 981 'and 978 for the energization of the lower winding of the end of numbering relay R 980, in such a way that the latter relay operates. When operating, the end of numbering relay R 980 closes, at contacts 988, a bonding circuit passing through contacts 964 'for the energization of the upper winding of said relay and interrupts, at contracts 986 and 987. , the circuits previously traced for excitement

  <Desc / Clms Page number 181>

 of the upper and lower windings of the response relay R 975, which effectively prevents the operation of the latter relay, which occupies the rest position at this time since it is of the differential type. On the other hand, the end of dialing relay R 980 interrupts, at contacts 981 ',

   the original circuit previously drawn for the application of an earth potential, through the intermediary of the lower winding of said relay and of the contacts 978 and 981 ', to the control conductor 0 1042 of the junction 1040 and from there through the original circuit previously traced, for the excitation of the lower winding of said relay.



  In addition, the end of numbering relay R 980 closes, at contacts 989, a direct circuit passing through contacts 961 ', 944, 931 and 922 for the application of an earth potential to the control conductor C 1042 of the junction 1040.



  In addition, the active recorder-transmitter is released automatically at this time. The application of the earth potential on the control conductor C 1042 of the junction 1040 causes the lighting of the monitoring lamp before the long distance operator position 1061, associated with the selector of the selector finder junction 1062, so as to indicate to the operator of said table that the call in progress routed through the selector of the searcher-selector junction 1062 to the called subscriber station T 41 of the main office 40 has not yet been the subject of 'answer.



   In addition, the end of numbering relay R 980 closes, at contacts 983 ', a variant circuit passing through contacts 972 and 1026 for the application of an earth potential to the signal output conductor C 903 and inter-. breaks, at contacts 984, the original circuit previously

  <Desc / Clms Page number 182>

 layout for the application of an earth potential to the signal output conductor C 903, so that the signal output relay R 997 of the powerline carrier 994 is kept in its operating position.

   On the other hand, the end of numbering relay R 980 interrupts, at contacts 981, the additional termination circuit previously traced and comprising the capacitor 917 and the resistor 918 in shunt on the line conductors C 901 and C 902 terminating to power line carrier equipment 994. In addition, the end of numbering relay R 980 interrupts, at contacts 982 and 984, the previously traced loop circuit leading to the upper and lower windings of the line relay R 1010 closes, to contacts 983 and 984, circuits for the application of an earth potential, through the windings of the fault relay R 1020, and of the second call relay R 970 respectively, to the line conductors C 1041 and C 1042 from junction 1040.

   More precisely, the earth potential is applied, via the winding of the fault relay R 1020, of the contacts 983 and 966, of the winding 913 of the translator RC 910 and of the contacts 964, to the line conductor. C 1041 from junction 1040, while the earth potential is, on the other hand, applied via the winding of the second call relay R 970, contacts 1022, 985 and 967, from the en - bearing 914 of translator RC 910 and contacts 969, to line conductor C 1042 of junction 1040; At this time, the train of trunk switches 805 tests the subscriber line 841 terminating at the called subscriber station T 41 of the main office 40 to determine whether said line is free or busy, as previously indicated.

   Assuming that subscriber line 841 is free at this time, trunk switch traLn 805

  <Desc / Clms Page number 183>

 applies an inrush current to said line and sends back tone current to junction 806 and arrival selector 812, to junction 875. Said return tone current flows through the previously traced connection comprising windings 876 ' and 877 'of the RC 875 translator and induces a caller alert tone current of the corresponding called party call in the coils 878' and 879 'of said translator. This induced current passes through the line conductors C 801 and C 802 and reaches the carrier current device 894.

   The balanced modulator of the carrier current equipment 894 responds by modulating the carrier signal at 24.55 kilocycles and by transmitting the acoustic component of said signal on the line conductors C 901 and C 902 and the windings 911 and 912 of the translator. RC 910. A corresponding return tone current is then induced in the windings 913 and 914 of said translator and applied to the previously traced circuit comprising junction 1040 and seeker-selector junction 1062 at the calling long distance operator position 1061. of the automatic long distance table 1060 of the remote office 50, which indicates to the operator of said position that the called subscriber station T 41 of the main office 40 is called.



  When the subscriber of the called station T 41 answers the call, the train of interuban switches 805 interrupts the return of the tone current back through the connection previously traced, to the requesting trunk operator position 1061, and reverses in besides the polarity of the junction 806 and consequently of the incoming selector 812 and of the junction 875. In this way, the left winding of the response relay R 890 of the junction circuit 800 is polarized in such a way that he works.

   When operating, the response relay

  <Desc / Clms Page number 184>

 R 890 closes an obvious circuit at contacts 891 for the application of an earth potential to the signal output conductor C 803, which causes the signal output relay R 897 of the signal output relay to be energized. powerline carrier 894 and de-energizing the signal input relay R 995 of carrier current gear 994, so that the latter relay closes, at contacts 996, an obvious circuit for the application of an earth potential at the signal input conductor C 904, which causes the signal input relay R 920 of the junction circuit 900 to operate. When operating, the signal input relay R 920 interrupts, at contacts 922,

   the direct circuit previously traced for the application of an earth potential to the control conductor C 1042 of junction 1040. The front monitoring lamp of the interurban operator position 1061 associated with the searcher-selector junction 1062 is then off, which indicates 8. the operator of said position that the call routed through a selector of the searcher-selector junction 1062 to the called subscriber station T 41 of the main office 40 received a response at this time. the operator of the calling long distance position 1061 of the automatic long distance switchboard 1060 of the remote office 50 enters into conversation with the subscriber of the called set T 41 of the main office 40 and advises him that a call is intended for her.

   The transmission on the carrier link of acoustic signals between the long distance operator position 1061 and the called subscriber set T 41 is substantially identical to that previously described.



  The carrier signal at 24.55 kilocycles modulated by the acoustic signal is transmitted from the carrier current apparatus 994 and the carrier signal at 15.95 kilocycles modulated by the acoustic signal is transmitted from the carrier current apparatus 994 to the powerline carrier equipment 894. At this

  <Desc / Clms Page number 185>

 At the moment, the operator in the long distance position I06I can interrupt the connection with the searcher-selector junction 1062 by establishing another connection between the subscriber set.
 EMI185.1
 andé née requested T 41 from main office 40 and the original call that was previously answered at long distance operator position 1061 using the finder selector junction finder.



   At the end of the established communication, when the subscriber of the called set T 41 of the main office 40 hangs up, the train of interurban switches 805 again inverts the polarity of the junction 806 so as to cause the relay to de-energize. response response R 890 of junction circuit 800 and therefore that of signal output relay R 897 of powerline carrier equipment 894. The signal input relay R 995 of power line carrier is then activated again and de-energizes the signal input relay R 920 of the junction circuit 900.



  By releasing its armature, the signal input relay R 920 closes, at contacts 922, the direct circuit previously drawn for the application of an earth potential to the control conductor C 1042 of junction 1040, which turns on the front monitoring lamp of the long distance attendant position 1061 associated with the selector of the searcher junction selector 1062, indicating to the operator of the long distance position 1061 of the automatic long distance panel 1060 of the remote office 50 that the subscriber of the requested set T 41 from main office 40 hung up.



   From the above description of the transmission of the end of conversation signal between the called subscriber station T 41 at the main office 40 and the long distance operator position 1061 of the Strowger automatic trunk switch 1060 at the remote office 50 , we will understand that the subscriber of the requested set! - !! can transmit using its communication hook

  <Desc / Clms Page number 186>

 mutation of the call signals at the operator position 1061 of the automatic trunk switch 1060 in a substantially identical manner by a suitable manipulation of said hook, which causes a corresponding operation of the train of trunk switches 805 with inversions alternate polarity of junction 806,

   so that the response relay R 890 of the junction circuit 800 operates accordingly and causes a corresponding operation of the signal input relay R 920 of the junction circuit 900, all in the manner previously discussed. Each time the R920 signal input relay releases its armature and then attracts it again, it closes, then interrupts, at contacts 922 the circuit previously traced for the application of an earth potential to the control conductor. C 1042 of junction 1040, which causes a corresponding flicker of the monitoring lamp before the long distance attendant position 1061 associated with the selector of the selector finder junction 1062.

   This flickering of the front monitoring lamp of the long distance operator position 1061 indicates to the operator of the long distance operator position that the subscriber of the called station T 41 of the main office 40 needs her services. As a result, she again actuates the key associated with the seeker-selector junction 1062 by establishing a connection between the seeker-selector junction 1062 and the long distance operator position 1061. At this time, the operator in position d The interurban operator 1061 of the automatic interuibain switchboard 1060 of the remote office 50 can again enter into a conversation with the subscriber of the called set T 41 of the main office 40.



   By receiving the end of conversation signal, the operator of long distance position 1061 can release the selector finder junction 1062, whether it is connected or

  <Desc / Clms Page number 187>

 no to the trunk attendant position 1061 by handling the appropriate trunk release key. At this moment, the searcher-selector junction 1062 is released and the earth potential which was applied to the control conductor C 1043 of the junction 1040 is eliminated, which interrupts the previously drawn circuit which kept the R 955 attack relay actuated. of the junction circuit 900, after which the latter relay releases its armature a short time later, since it is of the delayed release type.

   By releasing its @ - mature, the attack relay R 955 interrupts, at contacts 956, the multiple circuits previously drawn which kept the switching relay R 960 and the second call relay RI025 actuated, so that the switching relay R 960 releases its armature immediately and the second call relay R 1025 a short time later, since the latter relay is of the delayed release type.

   By releasing its armature, the switching relay R 960 interrupts, at contacts 964 ', the bonding circuit previously drawn for the excitation of the upper winding of the end of numbering relay R 980, so that the latter relay releases its armature in its turn, By releasing its armature, the end of numbering relay R 980 interrupts, at contacts 983 ', the variant circuit previously drawn for the application of an earth potential to the signal output conductor C 903 , which causes the de-energization of the signal output relay R 997 of the powerline carrier equipment 994 and, consequently, the re-energization of the signal input relay of the carrier current equipment 894,

     So that the signal input relay R 860 of the junction circuit 800 is deenergized. At this time, a battery potential is applied through the winding of the drive relay R 955 of the junction circuit 900, to the control conductor

  <Desc / Clms Page number 188>

 C 1043 of junction 1040, which indicates junction 1040 and, therefore, junction circuit 900 as being free to the selector of the searcher-selector junctions 1062 ect ... which have access to said junction and to said circuit.



   By releasing its armature, the signal input relay R 860 of the junction circuit 800 interrupts, at contacts 862, the circuit previously drawn which kept the bonding relay R 850 actuated, so that the latter relay releases its armature for a short time. instant later since it is of the delayed release type. On the other hand, the signal input relay R 860 interrupts, at contacts 863, the loop circuit connecting the left winding of the response relay R 890 of the junction circuit 800 to the inter-city switch train 805.

   By releasing its amature, the bonding relay R 850 interrupts, at contacts 851, the circuit previously drawn for the excitation of the right-hand winding of the response relay R 890 and interrupts, at contacts 852, the circuit previously drawn. which kept the switching relay R 880 activated. In addition, the gluing relay R 850 interrupts, at contacts 853, the circuit previously drawn for switching on the occupancy lamp L 817, which indicates to the operator of the switchboard 765 of the main office 40 that the junction circuit 800 terminated by the jack J 815 is free at this moment.

   By releasing its armature, the communication relay R 880 interrupts, at contacts 888, the circuit previously drawn for the application of an earth potential to the control conductor C 878 of junction 875, which brings about the release of the train. of interurban switches 805 and of the arrival selector 812. When the train of interurban switches 805 is thus released, the line circuit 842 associated with the subscriber line 841 which terminates at the subscriber station T 41 of the main office 40 indicates the subscriber line

  <Desc / Clms Page number 189>

 841 as being free to trunk switch train 805 and city switch train 844, which have access to said line.



   At this moment, the communication established between the calling trunk operator position 1061 of the automatic trunk switchboard 1060 of the remote office 50 and the called subscriber station T 41 of the main office 40 is interrupted and all the devices interested in said telephone. communication are completely released and become available for later use.



   In the above description of the routing of a call between the calling long distance operator position 1061 of the automatic trunk panel 1060 of the remote office 50 and the called subscriber station T 41 of the main office 40, we assumed that when the toll switch train 805 selected subscriber line 841 terminating at called subscriber station T 41, station T 41 was free.



  But it may happen that the requested subscriber station T 41 is busy at this time. Under these conditions, the train of long distance switches 805 observing by the test that the called subscriber set T 41 is busy reverses on the one hand the polarity of the junction 806 and, on the other hand, returns a dial tone current. busy on said junction, so that the response relay R 890 of the junction circuit 800 operates by causing the signal output relay R 897 of the powerline carrier 894 to be energized and, consequently, de-energized. ion of the signal input relay R 995 of the power line switchgear 994. The signal input relay R 920 of the junction circuit 900 releases its armature, all in the manner explained previously.

   By releasing its armature, the signal input relay R 920 closes at contacts 922, the direct circuit previously drawn for

  <Desc / Clms Page number 190>

 the application of an earth potential to the control conductor, of C 1042 of junction 1040, which turns off the front monitoring lamp of the long distance operator position 1061 associated with the selector of the searcher junction selector 1062, so that the operator at trunk position 1061 receives an answer signal.

   However, at this point, the busy tone current from the trunk switch train 805 at main office 40 is returned to the connection previously mapped to the trunk operator position 1061 of the automatic trunk switch 1060 at remote office 50. in the manner previously discussed, so that the busy tone current flowing through the attendant set at position 1061 indicates to the attendant at said position, in addition to the answer signal described above, that made the call has not been answered by the called subscriber set T 41 of the main office 40, but on the contrary the called subscriber set T 41 of the main office 40 is busy at that moment and that the desired communication cannot be established because of this condition.

   The operator of the trunk position 1061 of the automatic trunk switchboard 1060 then manipulates the front release key associated with the selector of the searcher-selector junction 1062 so as to cause the release of the junction circuit 900 of the power line equipment 994, powerline carrier equipment 894, junction circuit 800, arrival selector 812, and trunk switch train 805, all in the manner previously discussed.

   Subsequently, the operator of the trunk position 1061 of the automatic trunk switchboard 1060 can again manipulate her keypad, so that the recorder-transmitter in service causes the selector of the searcher-selector junction to operate again.

  <Desc / Clms Page number 191>

 
1062 and a new route of the call to the called subscriber station T 41 of the main office 40. A new test performed at this time by the train of inter-city switches 805 determines whether said station is free or busy.



   Considering again the operation of the trunk switch train 805 of the main office 40, when routing the communication described above between the trunk operator position 1061 of the automatic trunk switch 1060 of the remote office 50 and the called subscriber station T 41 of the main office 40, it will be noted that said train of switches operates during the transmission of several digits by the recorder-transmitter in service on the previously traced connection comprising the junction 806 leading to said train, since this has a corresponding number of switching stages.



  As a result, any given switching stage of the trunk switch train 805 may find all subsequent trunk switching stages occupied. Under these conditions, said stage reverses the polarity of the interurban switch train 805 causing premature operation of the response relay R 890 of the junction circuit 800 and a corresponding premature operation of the signal input relay R 920 of the junction circuit 900, all in the manner described above. Consequently, in the particular case considered, the signal input relay R 920 of the junction circuit 900 operates before the transmission of all the digits recorded in the transmitter recorder in service associated with the searcher-selector function 1062 at the time considered. .

   This operation of the R 920 signal input rolais is triggered before the operation of the end of dialing relay R 980 and while the response relay

  <Desc / Clms Page number 192>

 R 975 is de-excited. When operating, the signal input relay R 920 interrupts, at contacts 922, the circuit previously drawn for the energization of the upper winding of the response relay R 975, so that the latter relay operates since 'it is of the differential type.

   When operating, the response relay R 975 interrupts, at contacts 978, the circuit previously drawn for the application of an earth potential, via the lower winding of the numbering relay R 980, to the conductor of controls 0 1042 of junction 1040 and closes, at contacts 977, a circuit passing through contacts 981 'for the application of a battery potential, by means of resistor 924, to the control conductor C 1042 .

   When the earth potential applied through the resistor is thus removed from the control conductor C 1042 of the junction 1040 and replaced on this conductor by a battery potential also applied through a resistor, any subsequent operation of the transmitter recorder in service connected to the searcher-selector junction 1062 is disabled at this time. More precisely, because the operation of the transmitter recorder cannot continue, the timing device incorporated in said recorder times the operation of the transmitter recorder in service by completing a circuit which flashes one hundred and twenty times per minute. the long distance attendant position busy lamp 1061.

   This flickering of the busy lamp in question indicates to the operator of the trunk position 1061 that the transmitter recorder in service connected to the searcher-selector junction 1062 is blocked at the time considered due to a condition. total occupancy of the interurban switch train 805 at main office 40. The operator of the long distance position

  <Desc / Clms Page number 193>

 1061 then lowers the keypad error key causing the release of the transmitter recorder in service. Circuit changes are then caused and the busy lamp shown above flickers sixty times per minute, indicating to Moderator of trunk position 1061 that the transceiver has been released at this time. of the finder-selector junction 1062.

   Trunk operator 1061 then proceeds to release the finder-selector junction 1062, and therefore, all main office devices 40 including trunk switch train 805, all in the manner set forth. previously.



   From the above, it will be understood that the inbound selector 812 of the main office 40 is responsive to a full occupancy condition of the trunk bundle including the trunk 806 in an identical manner and causes a reversal. polarity on junction 875 and, consequently, premature operation of response relay R 890 of junction circuit 800, leads to premature operation of signal input relay R 920 of junction circuit 900. The front monitoring lamp of the long distance attendant position I06I associated with junction 1062 is consequently switched on and off at the rate of five times per minute, which gives the attendant a full busy signal, all of this. in the manner explained above.



   On the other hand, with respect to the operation of each trunk switching stage of the trunk switch train 805 of the main office 40, it will be appreciated that some predetermined trunk switching stage may be of the multi-select type. levels, so that considerable time is required after receiving a digit before the switching stage in question is

  <Desc / Clms Page number 194>

 can determine if all available output lines r are busy.

   In this case, the predetermined trunk switching stage reverses the polarity of junction 806 during its multi-level selection operation. Accordingly, when the predetermined trunk switching stage completes its multi-level selection and finds output line, it restores the polarity of junction 806. Accordingly, basing the selection operation on several levels of the toll switching stage of toll switch train 805, the polarity of junction 806 is maintained. inverted,

   which causes during this time interval a premature operation of the response relay R 890 of the junction circuit 800 and a corresponding premature operation of the signal input relay R 920 of the junction circuit 900. As a result, the relay d The signal input R 920 is kept actuated for the specified time interval and keeps the response relay R 975 itself actuated, after which, at the end of the specified time interval, the response relay R 890 of the junction circuit 800, the signal input relay R 920 and the response relay R 975 of the junction circuit 900 all three release their anchor.

   As a result, the response relay R 975 of the junction circuit 900 is kept actuated for the indicated time interval, so that first of all the earth potential applied through a resistor is replaced on the control conductor C 1042 of the junction 1040 by a battery potential also applied via a resistor, after which said battery potential is again replaced by an earth potential applied via a a resistance.

   Consequently, during the indicated time interval, the application of the battery potential, via the resistor, to the control conductor C 1042 of the junction 1040.

  <Desc / Clms Page number 195>

 stop the operation of the recorder-transmitter in service which is connected to the finder-selector junction 1062 and initiates a counting operation, However, the time interval in question is not long enough to bring about a total count of the operation of the recorder-transmitter in service in the manner set out above, so that subsequent operation of the indicated transmitter-recorder continues when the earth potential is reapplied through a resistance to the control conductor C 1042 from junction 1040,

     
Accordingly, after the operation of each trunk switch stage of the trunk switch train 805 at main office 40, there is a possibility that the transceiver associated with the seeker-selector junction 1062 at remote office 50 is blocked for a period of time. brief time interval to give the trunk switch stage of the trunk switch train 805 time to complete its multi-level select operation or other operation requiring some time.

   However, after all the digits stored in the running transmitter recorder connected to the selector finder junction 1062 have been transmitted assuming that no blocked trunk switching stages are encountered in the 805 trunk switch traLn, the recorder- transmitter in service operates by causing the application of the battery potential to the control conductor C 1042 of the junction 1040, which causes the operation of the end of numbering relay R 980 of the junction circuit 900, all in the manner previously explained .



   CALL FROM THE OPERATOR SWITCH PANEL
FROM THE MAIN OFFICE 40 AND DESTINED TO THE INTER-
 EMI195.1
 URBAIN AUTOMArrIQUE STROWGER DU BUR1UU EIp TGN'r: 50.- We will first of all assume that the operator of the switchboard

  <Desc / Clms Page number 196>

 switch 765 at main office 40 answered a call using the P 748 front plug of DICORDE 766 and requiring routing by an operator of the automatic trunk switch 1060 at remote office 50.

   The operator of the switchboard 765 inserts the rear plug P 758 of the dichord 766 into a jack terminating a free junction circuit of the group comprising the junction circuit 800, for example the J 815 jack which precisely terminates said junction circuit 800. when the junction circuit 800 is thus attacked, the power line switchgear 894 is in turn attacked and it attacks the power line equipment 994 via line 80. The junction circuit 900 is then attacked and attacks in turn, via junction 1030, arrival selector 1036, all in the manner previously discussed.



   Empress of the switchboard 765 then actuates the call dial D 760 incorporated in the dicorde 766 assuming that the dialing key K 737 has previously been brought to its rear position, according to the single digit designated as the call number of the remote office 50 automatic trunk board 1060. This single digit may be, for example, "0". When the number "0" is formed on the call dial of the operator switch panel 765, it is passed back through the junction circuit 800 to the powerline equipment 894, thence to the powerline equipment 994. , then to the junction circuit 900 and finally to the arrival selector 1036, all in the manner described above.

   Incoming selector 1636 responds to the number "0" by selecting the trunk bundle comprising junction 1065 and then, in that bundle, a free junction. For example, inbound selector 1036 can precisely select trunk 1065 which terminates at terminating trunk 1066. Inbound trunk trunk 1066 then places a call on output trunk 1067 and initiates

  <Desc / Clms Page number 197>

 the operation of the dispensing device incorporated in the automatic trunk switchboard 1060. The call can then be answered by one of the long distance operator positions of said switchboard, for example the operator position long distance 1061.

   The operation of a free searcher-selector junction individually associated with the long distance attendant position 1061, for example the searcher-selector junction 1062, is initiated. Specifically, the selector finder junction finder 1062 selects the output junction 1067 which starts from the incoming trunk junction 1066.

   Said finder-selector junction 1062 is now connected to trunk operator position 1061, so that the switchgear of trunk operator position 1061 eliminates the earth potential which was applied to the earth conductor of junction 1067 which starts from the incoming interurban junction 1066 and replaces it with a battery potential applied through a resistor, such that the earth potential which was applied to the control conductor C 1054 of junction 1030 be replaced by a battery potential applied through a resistor.

   When the earth potential is thus replaced on the control conductor C 1034 of the junction 1030 by a battery potential applied through a resistor, the circuit previously drawn passing through the contacts 933 and 986 for the excitation of the upper winding of the response relay R 975 is interrupted and said upper winding is short-circuited, so that the response relay R 975 operates, since it is of the differential type.

   When operating, the response relay R 975 interrupts, at contacts 976, the original termination circuit previously

  <Desc / Clms Page number 198>

 trace comprising the capacitor 917 and the resistor 918 in shunt on the line conductors C 901 and C 902 which terminate at the carrier current apparatus 994 and closes, at the contacts 979, the circuit previously drawn for the application of a potential earth to the signal output conductor C 903, so as to cause the energization of the signal output relay R 997 of the power line carrier 994 and, consequently, a new energization of the input relay of signals R 895 from the power line carrier 894. The signal input relay R 860 of the junction circuit 800 is then energized, all in the manner described above.

   While operating, the signal input relay R 860 interrupts, at contacts 861 the circuit previously drawn for the excitation of the lower winding of the plug relay R 820 in parallel with the upper winding of said relay and in series. with the winding of the rear monitoring relay R 755, so that the plug relay R 820 of the junction circuit 800 is kept in its working position and so that the rear monitoring relay R 755 of the dicorde 766 releases its reinforcement, given that it is of the marginal type. By releasing its ammature, the rear monitoring relay R 755 interrupts, at contacts 756, the circuit previously drawn for the lighting of the rear monitoring lamp L 757, which gives the operator of the switch panel operator 765 of the response control signals.



  * At this time, assuming that in dicorde 766 the dialing key K 737 has been returned to its normal position and that the back talk key K 735 has been activated, communication is established between the table and the attendant switch requestor 765 from main office

  <Desc / Clms Page number 199>

 40 and the requested long distance operator position 1061 of the automatic trunk panel 1060 of the remote office 50, and the operator of the switch panel 765 informs the operator of the long distance position 1061 regarding the subsequent routing of the call.

   The transmission over the powerline carrier link of acoustic signals between the calling operator switch panel 765 at main office 40 and the requested trunk operator position 1061 of the automatic trunk panel 1060 at remote office 50 is substantially identical to that previously. described ,. The carrier signal at 24.55 kilocycles modulated by the acoustic signal is transmitted by the carrier current apparatus 894 to the carrier current apparatus 994, and the carrier signal at 15.95 kilocycles modulated by the acoustic signal is transmitted. by carrier current equipment 994 to carrier current equipment 894.



   The operator of the trunk position 1061 then activates her keypad in such a way that the transmitter recorder in service can control the searcher-selector junction selector 1062 and the other trunk switching stages of the outgoing trunk switch train. After the communication has been routed on the outgoing circuit from the remote office 50, by the selector of the searcher-selector junction 1062, the operator of the trunk position 1061 withdraws from the communication by returning the conversation key from the searcher-selector junction 1062 to the idle position, which disconnects it from the long distance operator position 1061.

   On the other hand, the operator of the attendant switchboard 765 can withdraw from the call at this time by restoring the rear conversation key K 735 of the dicorde 766.



   During the routing of the call described above

  <Desc / Clms Page number 200>

 if it is necessary for the operator of the calling switchboard 765 of the main office 40 to re-enter into communication with the operator of the inter-city operator position 1061 of the automatic trunk 1060 of the remote office 50, this operation can be carried out by the operator of the switchboard 765 by bringing the call key K 736 to its rear position, which ensures the transmission of an inrush current signal by the interrupt generator 738 on the rear plug P 758, the jack 815 and the previously drawn circuit comprising the winding of the second call relay R 865 of the junction circuit 800,

   so that the second call relay R 865 operates a short time after the energization of its winding and then releases its armature a short time after the de-energization of said winding, given that this relay is both of the delayed attraction type and of the delayed release type. On operation, the second call relay R 865 interrupts, at contacts 868, the previously drawn circuit which kept the signal output relay R 830 activated and, at contacts 866, the previously drawn circuit which kept the relay activated. R 870 second call relay. The R 830 signal output relay releases its armature immediately and the R 870 second call relay a short time later since the latter relay is of the delayed release type.

   By releasing its armature, the second call relay R 870 closes, at contacts 871, a variant circuit comprising the contacts 867 and 821 for the energization of the signal output relay R 830. When the second call relay R 865 then releases its armature, it closes, at contacts 868, the original circuit previously drawn for the excitation of the signal output relay R 830, it closes at contacts 866, the original circuit previously drawn for the excitation of the second relay call R 870 and it interrupts, at contacts

  <Desc / Clms Page number 201>

 867, the variant circuit drawn above for energizing the R 830 signal output relay.

   Consequently, when the call key K 736 of the dicorde 766 is actuated, the second call relay R 865 of the junction circuit 800 causes the signal output relay R 830 to be energized and re-energized for a short time. instant later when the R 870 second call relay releases its armature. In this way the signal output relay R 830 releases the armature and then attracts it again after a short time, causing the corresponding de-energization and re-energization of the signal output relay R 897 of the device. current carrier 894 and a corresponding de-energization and re-energization of the signal input relay R 995 of the carrier current equipment 994.

   The signal input relay R 920 of the junction circuit 900 releases its armature and then pulls it in again after a short time.



   When the signal input relay R 920 releases its armature and then attracts it again, it closes, then interrupts, at contacts 922, the circuit previously drawn for the energization of the numbering relay R 940, so that the latter relay energizes and de-energizes a short time later since it is of the delayed release type. Consequently, when the call key K 736 of the dicorde 766 is brought to its rear position, the numbering relay R 940 of the junction circuit 900 attracts its armature and then releases it. This cycle is repeated by the interrupt generator 738.

   Each time the numbering relay R 940 attracts its armature and then releases it, it closes, then interrupts, at contacts 943, an obvious circuit for the application of an earth potential to the control conductor C 1034 of the junction. 1030, which causes the rear monitoring lamp to flicker from the operating position.

  <Desc / Clms Page number 202>

 long distance telephone 1061 associated with the searcher of the searcher-selector junction 1062. Consequently, when the call key K 736 of the dicorde 766 is brought to its rear position by the operator of the switchboard 765 of the main office 40, the rear monitoring of the interurban operator position 1061 associated with the searcher of the searcher-selector junction 1062 flickers,

   which indicates to the operator of the long distance operator position 1061 of the automatic long distance switchboard 1060 the recall condition of the established communication passing through the searcher of the searcher-selector junction 1062. The operator of the long distance position 1061 then actuates the conversation key of the searcher-selector junction 1062 so as to reconnect it to the long distance operator position 1061. The operator of the long distance position 1061 of the automatic long distance table 1060 of the remote office 50 can re-enter the conversation with the operator at switchboard 765 in main office 40.

   Then, the operator of the long distance position 1061 returns to the idle position the conversation key of the searcher-selector junction 1062 of the long distance operator position 1061.



   At the end of the established communication, the operator of the requesting switchboard 765 of the main office 40 removes the rear plug P 759 of the dicorde 766 from the jack J 815 which terminates the junction circuit 800, so that the rear monitoring relay R 755 of dichord 766, the plug relay R 820 and the jack relay R 835 of the junction circuit 800 releasing their armature, all in the manner previously explained. By releasing its armature, the R 835 jack relay causes the de-energization, a short time later, of the second call relay R 870 which is of the delayed release type and, by releasing its armature, the R 820 plug relay. causes the de-energization of the

  <Desc / Clms Page number 203>

 output of signals R 830, all in the manner described above.

   By releasing its armature, the signal output relay R 830 causes the de-energization of the signal output relay R 897 of the power line carrier 894 and, consequently, the re-energization of the signal input relay R 995 of the Powerline carrier equipment 994 The signal input relay R 920 of the junction circuit 900 is then de-energized, all in the manner discussed above. By releasing its armature, the R 920 signal input relay causes the R 930 bonding relay to be de-energized a short time later, since the latter relay is of the delayed release type. This latter relay then closes, at contacts 931, a circuit passing through contacts 922 and 944 for the application of an earth potential to the control conductor C 1034 of junction 1030.

   This application of an earth potential to the control conductor C 1034 of junction 1030 causes a stable lighting of the rear monitoring lamp of the interurban operator position 1061 associated with the finder of the seeker-selector junction 1062, this which indicates to the operator of said position that the communication established using the searcher-selector junction 1062 has been interrupted by the operator of the switchboard 765 of the main office 40. On the other hand, by releasing its armature, the bonding relay R 930 interrupts, at contacts 934, the original circuit previously drawn for the excitation of the lower winding of the response relay R 975.

   However, an additional holding circuit for energizing the lower winding of the R 975 response relay is closed at this time due to the application of an earth potential, in the seeker-selector junction 1062, at the con - control conductor of junction 1067, and consequently, to the control conductor C 1035 of junction 1030. For

  <Desc / Clms Page number 204>

 elsewhere, the sticking relay, R 930 interrupts, at contacts 933, the circuit previously drawn which short-circuited the upper winding of the response relay R 975. Consequently, given that the response relay R 975 is of the differentiated type 1, it is maintained in its actuated position at this time.

   In addition, the actuated response relay R 975 maintains closed, at contacts 978 ', a variant circuit for the application of an earth potential to the control conductor 0 1043 of junction 1040, thereby maintaining actually junction 1040 in the busy state with respect to the selector of the searcher-selector junctions 1062 ect ... which have access to said junction.-Finally, the response relay R 975 actuated maintains firm, at contacts 979, the Circuit previously drawn for the application of an earth potential to the 0 903 signal output conductor, which keeps the signal output relay R 997 of the power line equipment 994 activated.



   When the operator of the long distance position 1061 of the automatic long distance table 1060 receives the end of conversation signal as described above, she activates the junction release key associated with the searcher-selector junction 1062, so as to cause the call. release of seeker from seeker-selector junction 1062.



  The earth potential which was applied to the control conductor of junction 1067 from the incoming interurban junction 1066 and, consequently, to the control conductor C 1035 of the junction 1030 is then removed, which interrupts the circuit. variant previously drawn for the excitation of the lower winding of the response relay R 975 of the junction circuit 900, so that the latter relay releases its armature.

   On the other hand, when the seeker of the seeker-selector junction 1062 is thus released, the arrival selector 1036 is itself released, so that

  <Desc / Clms Page number 205>

 the incoming trunk junction 1066 is again indicated as free to the incoming selectors 1036 ect ... which have access to said circuit. By releasing its armature, response relay R 975 of junction circuit 900 interrupts, at contacts 978 ', the variant circuit previously indicated for the application of an earth potential to control conductor C 1043 of junction 1040 which is indicated as free to the selectors of the searcher-selector junction 1062 etc ..... which have access to said junction.

   Finally, the response relay R 975 interrupts, at contacts 979, the circuit previously drawn for the application of an earth potential to the signal output conductor C 903, so as to cause the de-energization of the relay. signal output R 997 of powerline carrier equipment 994 and, consequently, re-energization of signal input relay R 895 of power line carrier 894, so that the signal input relay R 860 of the junction circuit 800 releases its armature, all in the manner explained previously.



  By releasing its armature, the R 860 signal input relay causes the relay to de-energize. s bonding R 850 and the latter relay itself causes the de-energization of the switching relay R 880 which has been activated as a result of the de-energization of the jack relay R 835 as explained above. By releasing its armature, the switching relay R 880 causes the release of the arrival selector 812 which had been driven by the junction 875 as a result of the operation of the switching relay R 880, all in the manner explained previously.



   At this time, the communication established between the calling operator switchboard 765 of the main office 40 and the long distance operator position 1061 of the called automatic trunk panel 1060 of the office

  <Desc / Clms Page number 206>

 remote 50 is interrupted and all devices interested in said communication are (Encroachment released and become available for later use.
 EMI206.1
 



  CALL FROM TABLE I1V. i AUTavaTIC RURBAN
REMOTE OFFICE STROWGER 50 AND INTENDED FOR THE PRINCIPA 40 OFFICE OPERATING PANEL
It will first be assumed that the operator of a long distance position, for example the long distance operator position 1061 of the automatic long distance table 1060 of the remote office 50, has answered a call using the finder of a searcher-selector junction. individually associated with said position, eg, seeker-selector junction 1062, and requiring operator routing at switchboard 765 at main office 40.



  The operator in the trunk position 1061 activates the associated keypad, so that the recorder-transmitter in use operates by transmitting two corresponding digits.



  The first digit transmitted by the recorder-transmitter indicated produces the operation of the selector of the searcher-selector junction 1062 which selects the bundle of junctions comprising in particular the junction 1040, then, in this bundle, a free junction. For example, the selector of the seeker-selector junction 1062 can precisely select the junction 1040 which terminates at the junction circuit 900, so that the junction circuit 900, when driven, attacks itself. powerline carrier 994 and therefore through line 80 powerline carrier 894, after which junction circuit 800 is driven and in turn drives, through junction 875, the ar selector. - riveted 812, all in the manner described above.



   The indicated recorder-transmitter connected to the finder-selector junction 1062 then transmits the second or

  <Desc / Clms Page number 207>

 last digit stored on selector switch of seeker-selector junction 1062 and junction 1040 to line relay R 1010 of junction circuit 900, so that the digit in question is passed back to powerline carrier 994, then from there to powerline carrier equipment 894 then to the signal input relay R 860 of the junction circuit 800, and finally to the arrival selector 812, after which the indicated recorder-transmitter triggers the operation of the end of dialing relay R 980 of the junction circuit 900 then is automatically released, all in the manner explained previously.

   The arrival selector 812 responds to the number indicated by selecting the bundle of junctions comprising junction 808 and then, in this bundle, a free junction. For example, inbound selector 812 may precisely select trunk 808 which terminates at terminating trunk 809, so that terminating trunk 809 places a call on output trunk 810 which originates from terminating trunk 809 and terminates at jack J 811 in front of the switchboard 765 in main office 40.

   When the end of numbering relay R 980 of the junction circuit 900 operates as described above, it cuts off the response relay R 975 and the line relay R 1010 and connects the fault relay R 1020 and the control relay. second call R 970 to line conductors C 1041 and C 1042 of junction 1040, all in the manner described above.



   The table operator at switch 765 in main office 40 answers the call using a free dicord, for example dicorde 766, after which the rear plug P 758 of said dicorde is inserted into the J 811 jack which terminates the outgoing 810 junction. of the incoming long distance junction 809. When the rear plug P 758 of the dicorde 766 is thus

  <Desc / Clms Page number 208>

 inserted into jack J 811, the rear monitoring relay P 755 of dicorde 766 is maintained in its rest position, given that it is of the marginal type, keeping the rear monitoring lamp L 757 not lit, which indicates to the operator of switchboard 765, of the main office 40 that the call in question is being answered.



  On the other hand, the incoming trunk junction 809 is actuated and reverses the polarity on the junction 808 and, therefore, on the inbound selector 812 and junction 875, so that the left winding of the R answer 890 of the junction circuit 800 is biased in such a way that it operates. When operating, the R 890 response relay causes the R 897 signal output relay of the powerline carrier 894 to be energized and, consequently, the R 995 signal input relay of the power line switchgear de-energized. 994, so that the signal input relay R 920 of the junction circuit 900 is activated.

   When operating, the signal input relay R 920 interrupts, at contacts 922, the direct circuit previously drawn for the application of an earth potential to the control conductor C 1042 of junction 1040, which switches off the circuit. front monitoring lamp of the long distance attendant position 1061 associated with the selector of the searcher-selector junction 1062, indicating to the attendant in said position that the call routed through the selector of the searcher-selector junction selector 1062 at the requested operator switch board 765 at main office 40 was answered at this time.

   The operator of the requesting long distance position 1061 of the automatic long distance switchboard 1060 of the remote office 50 then informs the operator of the requested switchboard 765 of the main office 40 in

  <Desc / Clms Page number 209>

 as regards the routing of the communication, given that a communication is then established between these two operators at this time. The transmission over the powerline carrier link of acoustic signals between the requesting trunk operator position 1061 of the automatic trunk switchboard 1060 of the remote office 50 and the called operator switchboard 765 of the main office 40 is substantially identical to that previously described.



  The carrier signal at 24.55 kilocycles modulated by the acoustic signal is transmitted by the carrier current apparatus 894 to the carrier current apparatus 994, and the carrier signal at 15.95 kilocycles modulated by the acoustic signal is transmitted from l Powerline carrier equipment 994 to carrier current equipment 894.



   The operator of the switch panel 765 then returns the rear conversation key X 735 of the dicorde 766 to the rest position, said key having been actuated following the answer to the call made using the rear plug P 758. Then, The operator of the switchboard 765 places the dialing key X 737 of the dicorde 766 in its forward position and causes the routing of the communication by inserting the front plug P 748 into a jack terminating a free junction leading to the destination desired.

   When the call has been thus routed by the operator at switchboard 765 in main office 40, the dialing key K 737 and the front talk key K 734 are returned to their normal position, which establishes a communication between the front and rear plugs P 758 and P 748 of the dicorde 766 and, therefore, between the communication arriving at the main office 40, and the communication leaving said office.



  The operator at the switchboard 765 at main office 40 then withdrew from the established connection by returning

  <Desc / Clms Page number 210>

 in the idle position the rear conversation key 2: 735 and the front conversation key K 734 of dicorde 766. At this moment, the operator of the long distance position 1061 drops out of the call by returning to 1 has the idle position of the conversation key of the researcher-voter junction 1062, which disconnects it from the inter-urban operator position 1061 of the automatic trunk switchboard 1060 of the remote office 50.



   During the routing of the call described above, if it was necessary for the operator of the calling interurban position 1061 of the automatic trunk switchboard 1060 of the remote office 50 to re-enter into communication with the operator of the switchboard requested switch 765 from the main office 40, this operation could be performed by the operator in the long distance position 1061 by manipulating the call key associated with its forward position after a new actuation of the conversation key of the searcher selector junction 1062 , which would reconnect the searcher-selector junction 1062 to the trunk attendant position 1061.

   A battery potential would then be applied to the positive line conductor C 1042 of the junction 1040 of the seeker-selector junction 1062 by the associated interrupting generator and then eliminated from said conductor. The application of the battery potential to the line conductor C 1042 closes a circuit passing through contacts 969, the winding 914 of the RC translator 910, the contacts 967, 985 and 1022 for the energization of the winding of the second call relay. R 970 so that the latter releas attracts its frame a short time later since it is of the delayed attraction type.

   Consequently, when the associated call key is actuated at the trunk attendant position 1061, the second call relay R 970 of the trunk circuit 900 operates.

  <Desc / Clms Page number 211>

 then releases its frame. Each time the second call relay R 970 attracts its armature, it interrupts, at contacts 972, the circuit previously drawn for the application of an earth potential to the signal output conductor C 903 and interrupts, at contacts 971, the circuit. circuit previously drawn which kept the second call relay R 1025 actuated so that the latter relay releases its armature a short time later since it is of the delayed release type.

   By releasing its armature, the second call relay R 1025 closes, at contacts 1027, a variant circuit passing through contacts 983 'for the application of an earth potential to the signal output conductor C 903. Subsequent - when the second call relay R 970 releases its armature, it closes at contacts 971, the circuit previously drawn for the excitation of the second call delay R 1025 and, while operating, the second call relay R 1025 closes, to contacts 1026, the original circuit previously drawn for the application of a ground potential to the signal output conductor C 903.

   Accordingly, each time the second call relay R 970 is energized and then de-energized, an earth potential is removed from the signal output conductor C 903 and then reapplied to said conductor after a determined time interval. As a result, placing the call key in its forward position at the trunk attendant position 1061 causes periodic energization and de-energization of the second call relays R 970 and R 1025 of the trunk circuit 900, thus switching on and off. in the above manner, so that an earth potential is removed and reapplied repeatedly to the signal output conductor C 903, which causes a corresponding operation of the signal output relay R 997 of the '994 power line switchgear and,

  <Desc / Clms Page number 212>

 Therefore,

   signal input relay R 895 of the powerline carrier 894. the signal input relay R 860 of the junction circuit 800 operates in the same way and sends back to cortacts 863 corresponding pulses on junction 875, arrival selector 812 and junction 808, up to terminating trunk 809. Trunk trunk 809 responds by acting through the control conductor of junction 810 on the plug not shown of the jack J 811 and on the body of the rear plug P 758 of the dicorde 7669 so that the circuit passing through the contacts 751 for the excitation of the winding of the rear monitoring relay R 755 of the dicorde 766 is ordered accordingly.

   Specifically, the rear watchdog relay R 765 operates according to the indicated pulses by retransmitting them to contacts 756, so that the rear watchdog lamp L 757 flickers correspondingly - indicating the second call on the junction circuit 800 by l The operator of the trunk position 1061 of the automatic trunk panel 1060 of the remote office 50. The operator of the switch panel 765 is then back in communication by activating the rear conversation key K 735, so that the connection previously drawn between the headset 767 of the Main office 40 called attendant switchboard 765 and the remote office 50 auto-attendant switchboard 1061 is re-established.



  When the operator of the switchboard 765 is informed of the needs of the operator of the long distance position 1061, she again withdraws from the call by returning the rear conversation key K 735 of the dicorde 766 to idle.



   At the end of the established call, the operator of the calling interurban position 1061 of the inter-

  <Desc / Clms Page number 213>

 urban automatic 1060 actuates the junction release key associated with the seeker-selector junction 1062, which causes the selector to be released from said searcher-selector junction 1062. The earth potential which was applied to the conductor of command C 1043 of junction 1040 is then eliminated, which ensures the de-energization of the drive relay R 955 of the junction circuit 900 a short time later since the latter is of the delayed release type, in the manner previously explained .

   By releasing its armature, the attack relay R 955 causes the de-energization of the switching relay R 960 and that of the second call relay R 1025 a short time later, the latter relay being of the delayed release type. By releasing its armature, the switching relay R 960 causes the de-energization of the end of numbering relay R 980 and, by releasing its magnet, the end of numbering relay R 980 interrupts, at contacts 983 ', the circuit. previously plotted for the application of a ground potential to the key output conductor and signals C 903, which causes the de-energization of the signal output relay R 997 of the power line carrier 994 all in the manner explained previously .

   On the other hand, by releasing its armature, the switching relay R 960 closes, at the contacts 865 ', a circuit passing through the contacts 923 for the excitation of the bonding relay R 930, so that the latter relay closes, at the contacts 933 and 934, the circuits previously drawn for the excitation of the upper and lower windings of the response relay R 975. However, the latter relay does not operate at this time since it is of the differential type. On the other hand, the bonding relay R 930, closes, at contacts 934, the circuit previously drawn for the application of an earth potential to the conductor.

  <Desc / Clms Page number 214>

 C 1035 of junction 1030, which causes the input selector 1036 to be attacked, but has no effect at this time.



  Finally, the bonding relay R 930 interrupts, at contacts 936, the circuit previously drawn for the application of a battery potential, by means of the winding of the drive relay R 955, to the control conductor C 1043 of junction 1040 and closes, at contacts 935, the circuit previously drawn for the application of a ground potential to the control conductor C 1043, so that the junction circuit 900 keeps junction 1040 occupied with respect to the selectors of the seeker-selector junctions 1062 ect ... which have access to said junction, until junction circuit 800 of main office 40 is released.



   When releasing its armature, the R 997 signal output relay of power line carrier 994:. causes a new operation of the signal input relay R 895 of the power line carrier 894, which causes a de-energization of the signal input relay R 860 of the junction circuit 800. By releasing its armature, the R 860 signal input relay interrupts, at contacts 862, the previously drawn circuit which kept the R 850 bonding relay actuated, so that the latter relay releases its armature a short time later given that it is of the type with delayed release.

   By releasing its armature, the bonding relay R 850 interrupts, at contacts 852, the previously traced circuit which kept the switching relay R 880 actuated so that the latter relay releases its armature by interrupting, at contacts 888, the circuit previously trace for the application of an earth potential to the control conductor C 878 of junction 875, which causes the release of the arrival selector 812. On the other hand, by releasing its armature, the input relay of signals

  <Desc / Clms Page number 215>

 R 860 interrupts, at contacts 863, the loop circuit previously drawn between the left winding of the R 890 response relay and the arrival selector 812, so that the R 890 response relay releases its armature.

   Finally, by releasing its armature, the bonding relay R 850 interrupts, at contacts 851, the circuit previously drawn for the excitation of the right-hand winding of the response relay R 890 and interrupts, at contacts 853, the circuit. previously traced for the switching on of the occupancy lamp L 817, which indicates the condition of non-occupation of the junction circuit 800 at this moment. when the arrival selector 812 is thus released, the incoming trunk junction 809 causes the rear monitoring relay R 755 of the dicorde 766 to operate, so that the rear monitoring lamp L 757 is lit, this which indicates to the operator of the switchboard 765 that the communication has been interrupted.

   the operator of the switchboard 765 of the main office 40 then removes the rear plug P 758 of the dicorde 766 from the J 811 jack which terminates the junction 810 starting from the incoming trunk junction 809, so as to cause the relay to de-energize 766 dicorde rear surveillance R 755 and therefore the L 757 rear surveillance lamp extinguishes. At this time the incoming trunk junction 809 is released and indicates to the incoming selectors 812 etc ... who have access to junction 808 that said junction is occupied.



   By releasing its armature, the response relay R 890 of the junction circuit 800 causes the de-energization of the signal output relay R 897 of the power line carrier 894 and, consequently, a new energization of the input relay. signal R 995 of powerline carrier 994, so that the signal input relay R 920 of the junction circuit 900 is de-energized.

  <Desc / Clms Page number 216>

 



  By releasing its armature, the R 920 signal input relay causes the R 930 bonding relay to be de-energized a short time later, the latter relay being of the delayed release type. By releasing its armature, the bonding relay R 930 interrupts, at contacts 933 and 934, the circuits previously traced for the excitation of the upper and lower windings of the response relay R 975, the latter relay having already released its armature given that it is of the differential type. On the other hand, the bonded relay R 930 interrupts, at contacts 934, the circuit previously drawn for the application of an earth potential to the control conductor C 1035 of junction 1030, which brings about the release of the circuit. arrival selector 1036.

   Finally, the bonding relay R 930 interrupts, at contacts 935, the circuit previously drawn for the application of an earth potential to the control conductor C 1043 of junction 1040 and closes, at contacts 936, the circuit. original previously drawn for the application of a battery potential, through the winding of the drive relay R 955, to the control conductor C 1043, so that the junction 1040 is again indicated as free at the junctions selector, finder-selector 1062 ect ... which have access to said junction.



   At this time, the communication established between the calling toll operator position 1061 of the automatic toll panel 1060 of the remote office 50 and the requested operator switch panel 765 of the main office 40 is interrupted and every time. devices interested in said communication are completely released and become available for further use.



   DISCONNECTION OF A JUNCTION CIRCUIT BY
THE AUTOMATIC STROWGER INTERURBAN PANEL
OFFICE OFFICE 50.



   We will first assume that the operator of one

  <Desc / Clms Page number 217>

 long distance positions for example the long distance attendant position 1061 of the automatic trunk switchboard 1060 of the remote office 50, using one of the searcher-selector junctions, for example the seeker-selector junction 1062, attempts to route a communication to requested attendant switchboard 765 or to a called subscriber station at main office 40 as previously discussed. Assume on the other hand that the selector of the seeker-selector junction 1062 attacks the junction 1040 which terminates at the junction circuit 900 and that the junction circuit 900, for some reason, cannot route the communication.

   In this case, at the end of the transmission of all the digits recorded in the recorder-transmitter in service connected to the searcher-selector junction 1062, said recorder-transmitter is automatically released after having triggered the operation of the end of signal relay. numbering R 980 of the junction circuit 900, the whole in the manner explained previously.



  The operator in trunk position 1061, when she notices that trunk circuit 900 is not properly operated, manipulates an associated trouble key by causing battery potential to be applied to the conductors. line C 1041 and C 1042 of junction 1040. Applying the battery potential to the line conductor C 1041 closes the circuit previously drawn for the energization of the winding of the fault relay R 1020 and the application of the potential of battery to the line conductor C 1042 closes the circuit previously drawn for energizing the winding of the second call relay R 970 so that these two relays operate a short time later since they are both of the delayed traction type.

   While operating, the fault relay R 1020 interrupts, at contacts 1022, the circuit previously drawn which kept the second call relay R 970 actuated.

  <Desc / Clms Page number 218>

 and closes, at contacts 1021, a circuit substantially identical to that previously traced for the energization of the winding of the derating relay R 950, so that the latter relay, which is at the same time delayed attraction and delayed release, works a short time later.



  When operating, the fault relay R 950 closes, at contacts 952 ', a holding circuit passing through the fault key X 950 for energizing its winding and closes, at contacts 953', an obvious circuit for ignition. L 950 trouble lamp display, indicating to a repair worker that trunk 900 is out of order and requires repair. On the other hand, the fault relay R 950 interrupts, at contacts 951 ′ the circuit previously drawn for the excitation of the drive relay R 955, in such a way that the latter relay releases its armature a short instant later given that 'it's the delayed release type.

   Furthermore, the fault relay R 950 closes, at contacts 954, a circuit passing through contacts 936 for the application of an earth potential to the control conductor C 1043 of junction 1040, which indicates said function, and consequently the junction circuit 900 as being occupied with the selectors of the seeker-selector junctions 1062 etc ... which have access to said junction and to said circuit.

   On the other hand, the fault relay R 950 interrupts, at contacts 951, the previously traced termination circuit comprising the capacitor 917 and the resistor 918 in shunt on the line conductors C 901 and C 902 which terminate in the switchgear 994 and establishes, at contacts 952 and 953, a connection comprising capacitor 917 and resistor 918 between the trouble tone sources and line conductors C 901 and C 902, so that the carrier signal at 15.95 kilocycles is modulated and applied by the equipment

  <Desc / Clms Page number 219>

 powerline carrier 994, through line 80 to carrier current equipment 894.

   In this way, the acoustic component of said signal is applied to the line conductors C 801 and C 802 starting from the carrier current device 894 and passes through the windings 878 'and 879' of the translator RC 875, which induces a ten - corresponding disturbance tone signal in windings 876 'and 877' of the RC 875 translator.



   The operator of the trunk position 1061 of the automatic trunk switchboard 1060 of the remote office 50 then releases the searcher-selector junction 1062, so that all the relays of the junction circuit 900 are de-energized except for the fault relay. R 950.



  At this moment, the junction circuit 900 is indicated as occupied with the selectors of the searcher-selector junctions 1062 etc ... which have access to said circuit. In a similar way, the junction circuit 800 is traversed by a disturbance tone which the operator of the switchboard 765 of the main office 40 hears if she inserts the rear plug of one of the dicords of said board into the jack J 815 which terminates the junction circuit 800, which indicates the condition encountered to the operator of the switchboard 765.

   When the repair worker has restored the junction circuit 900 to proper working order, the fault key K 950 is actuated momentarily so as to interrupt the previously traced gluing circuit, which kept the fault relay R 950 actuated. This last relay releases its armature a short time later, since it is both of the delayed attraction type and of the delayed release type.

   By releasing its armature, the fault relay R 950 interrupts, at contacts 952 ', another point of the maintenance circuit which ensured the excitation of its winding and interrupts.

  <Desc / Clms Page number 220>

 at contacts 953 ', the circuit previously drawn for igniting the fault lamp L 950, which indicates that the junction circuit 900 is again in service.

   On the other hand, the fault relay R 950 interrupts, at contacts 952 and 953, the connection previously established between the source of the disturbance tone and the line conductors C 901 and C 902 which terminate in the switchgear. carrier 994, which caused the removal of the trouble tone application at the J 815 jack that terminates trunk 800 in front of the operator switch board 765 at main office 40.

   On the other hand, the fault relay R 950 closes, at contacts 951, the original terminating circuit previously drawn comprising the capacitor 917 and the resistor 918 in shunt on the line conductors C 901 and C 902 indicated, interrupts, at contacts 954, the circuit previously traced for the application of an earth potential to control conductor C 1043 of junction 1040 and closes, at contacts 951 ', the original circuit previously traced for the application of 'a battery potential through the winding of the drive relay R 955, to the control co-iducer C 1043. At this moment, the junction 1040 which leads to the junction circuit 900 is indicated as free at the selector junction selector selector 1062 etc ... which have access to said junction.



   CONCLUSION
From the foregoing description, it is evident that the invention makes it possible to obtain a telephone system comprising devices enabling telephone communications to be established between subscriber stations appending to different automatic exchanges via the telephone. intermediary of carrier current links and comprising on the other hand devices making it possible to establish telephone communications between subscriber stations of different automatic exchanges and an operator panel of the manual type belonging to a main office through

  <Desc / Clms Page number 221>

 diary of carrier current links.

   Finally, the invention also makes it possible to establish telephone communications between an operator panel of the manual type of a main office and an operator panel of the fully automatic type of a remote office ', also by means of links. powerline.



   It goes without saying that, depending on the applications envisaged, it will be possible to make modifications to the embodiments which have just been described, without leaving the cache of the invent # im CLAIMS I. - Telephone system in which a automatic switchgear is accessible to a subscriber station and in order to enter a junction circuit with a first and a second junction of either one of which can be used to enter the junction circuit, this system comprising means reacting to the occupation of the junction circuit, for entering a second switching device on a trunk line,

   after which one or more digits can be transmitted from this station through the switching apparatus accessible to it at the junction by means of which the junction circuit is seized, to the junction circuit itself. same and to the trunk line, to selectively actuate the second switching device in order to route the communication, this system also comprising a device counting transmitted digits, controlled by the transmission of a given number of digits on said junction, in view to block the transmission of another digit on the interurban line, to allow the first switch to enter the junction circuit on the other junction when, after routing of the connection by the second switch,

   the actuation of this second switch requires the transmission of a greater number of digits than said given number.



   2.- Telephone system according to 1, comprising, in association with the digit counter device, a device for blocking the transmission of another digit on the trunk line and for returning a corresponding signal.

  <Desc / Clms Page number 222>

 on the first junction selected in the set, to warn its user that the junction circuit must be entered on the other junction.



   3. - Telephone system according to 1, comprising a device for controlling the establishment of a connection, in which use is made of the second junction, to determine the charge for the set which has been forgotten the connection.



   4. - Telephone system according to 1, comprising, in the junction circuit, a device controlled by the establishment of a connection making use of the second junction intended to reverse the initial polarity of the battery supply of station 4 'where the call emanates.



   5. - Telephone system according to 4, in which the station which initiates the call is a prepaid station, this system comprising a device provided for the prepaid station and controlled by the reverse polarity of the battery, to block communication on the battery. connection, unless a coin or token has been inserted into the prepayment station.



   6. Telephone system according to 1, with a second junction circuit which can be facilitated by a device reacting to the occupation of the first junction of the first junction circuit, and a device reacting to the occupation of the telephone. second junction circuit, to enter the second switch, this system comprising, in the second junction circuit, means reacting to a number received on the trunk line, to repeat a number corresponding to the second switch, which routes the connection of this f açon.

  <Desc / Clms Page number 223>

 



   7.- Telephone system according to 6, comprising a powerline link interconnecting the 6 junction circuits for the purpose of entering the second trunk circuit via the powerline link, this link comprising the trunk line between the two junction circuits.



   8.- Telephone system selonn7, comprising, in the powerline link, intended to connect the junction circuits, a first carrier current device, connected to the first junction circuit, a second carrier current device, connected to the second trunk circuit, and a trunk line interconnecting these two devices, the first of these devices being seized following the occupation of the first junction circuit, and ensuring in turn the occupation of the second device via of the trunk line, this second device actuating means for entering the second junction circuit and, through the latter, the second switching device.



     9.- Telephone system according to 8, comprising, in the first junction circuit, means for repeating a digit received at the station at the first carrier current device, this device comprising means acting following the reception of a digit, to repeat a digit corresponding on the trunk line to said second power line equipment, in which this digit is repeated for transmission to the second trunk circuit, which transmits it to the second switch.



   10.- Telephone system according to 1; in which a first exchange serving a first group of stations comprises an automatic switchgear having access to a

  <Desc / Clms Page number 224>

 junction circuit in this exchange by means of a first and a second incoming channel, and in which a second exchange also provided with a second automatic switching device, serves a second group of stations, a trunk line interconnecting these exchanges, this system comprising an office with a switchboard (operator's table), the latter office being accessible to the second switchgear, this system further comprising means that can * be controlled from a calling station of the first group,

   to route a connection selectively through the first switchgear on either of the incoming paths to the first trunk circuit, to grab the second switchgear on the trunk line connecting the exchanges to a device can then be controlled from the calling station of the first group, to establish the connection.



   11.- Telephone system according to 10, comprising means actuated in the event that the connection is routed on the first incoming channel to the first trunk circuit to allow final routing of this connection to the switchboard and to block this connection. final routing to a called station of the second group.



   121- Telephone system according to 10 and 11, comprising means that can be actuated in the case where the connection is routed on the second incoming path to the first junction circuit, to allow the completion of the call at a station of the second group or switch panel.



   13.- Telephone system according to 12, comprising means controlled by reestablishing a connection routed on said second channel, to determine a charge to be paid.

  <Desc / Clms Page number 225>

 of the calling line of the first group.



   14.- Telephone system according to 10, comprising, in association with the second junction circuit in the second central, an arrival channel accessible to the second switchgear and a departure channel accessible to this same apparatus, and reactive means. to the occupation of the second junction circuit, to seize the second switchgear on the outgoing channel of the latter, in order to allow the routing of the call to the switchboard while blocking the final routing to a called station of the second group, this system further comprising means which can be actuated from a station of the second group,

   to actuate the second switchgear with a view to routing a connection to the switchboard or to the second junction circuit on the arrival path of said junction circuit.



   15, - Telephone system, according to 14, comprising means responsive to the routing of a connection to the second junction circuit, for entering the first junction circuit, means responding to the occupation of the first junction circuit, for enter the first switchgear on the outgoing channel of the first junction circuit and means that can be actuated from the calling station in the second group, to selectively actuate the first switchgear in order to route the connection to a station called from the first group.



   16.- Telephone system, according to 10 and 15, comprising actuated means in the event that the connection from the first station is routed to the first junction circuit on the second path, to be routed either to the switchboard , or to a called set of the second group, in order to determine a charge payable by the set

  <Desc / Clms Page number 226>

 caller from the first group.



   17.- Telephone system according to 7 and 12 to 16, with a first powerline link connecting the centers and a second powerline link connecting the second switchboard to the office, this system further comprising means that can be operated from a calling station of the first group, for routing a call on the first power line carrier link to the second switchgear, additional means being operable from the calling station of the first group through the first switchgear and of the first powerline carrier link, to selectively actuate the second switchgear in order to route the connection either to a called station of the second group, or on the second carrier current link, to the switchboard.



   18.- Telephone system according to 15 to 17, comprising means operable from the switchboard, via the second carrier current link, for selectively activating the second switchgear in order to route the connection. to a called station of the second group or to route the connection on the first powerline carrier link to the first switchgear, as well as additional means that can be actuated from the switchboard via the second powerline carrier link and the second switchgear and also via the so-called first carrier current link,

   to selectively operate the first switchgear to route the connection to a called station of the first group.



   19. - Telephone system according to 12 to 18, in which the calling station of the first group selectively actuates the first switchgear to route the connection

  <Desc / Clms Page number 227>

 from this either to another station of the first group, or, through the first power line power line, to the second switchgear, through the first power line link, to the second switch gear , or wherein said first calling station routes the call from said second switchgear on the second powerline link to the switchboard,

   while a calling station in the second group selectively actuates the second switchgear to establish a connection to the first switchgear through the first powerline link, or to route the call to the switchboard through the 'via the second powerline link, after which the calling station of the second group, acting through the second switchgear and the first powerline link, can operate the first switchgear to set up connection with a called station of the first group, while the switchboard can route a call via the second powerline link to the second switchgear for connection to a called station of the second group,

   or else, can route a call from the switch panel through the first powerline carrier link to the first switchgear, to terminate the call at a called station of the first group.



   20.- Telephone system according to 10, in which the exchanges serve groups of sets of different classes by means of an automatic switchgear provided in the exchanges or by means of the switchboard, this system comprising means controlled by a response operation performed at the switchboard

  <Desc / Clms Page number 228>

 for transmitting, through the first power line carrier link and the second switchgear and through the second power line carrier link, a signal indicative of the class of the calling station of the first group, and other means also actuated by a response operation performed at the switchboard, to transmit on the second powerline link,

   a signal indicative of the class of the calling station of the second group.



   21.- Telephone system according to 10, comprising means reacting to the establishment of a connection to a called station of the second group, to determine a charge payable by the calling station of the first group, whether this call has been established from a calling station of the first group to a called station of the same group, or to a called station of the second group.



   22. - Telephone system according to 21, comprising means which can be controlled from a calling station of the second group to selectively establish a connection either to a called station of the second group, or via the second powerline link, of the switchboard of the second switchgear and of the first powerline carrier link, to make a connection to a called station of the first group, and means reacting to the establishment of a connection to a called station of the first. croup, to determine a charge payable by the calling station of the second group.



   23. - Telephone system according to 10, comprising means reacting to hanging up by the calling station of the first group, to transmit a hang up signal via the first] Bison with carrier current of said second switching device and of the second link powerline carrier, to said switchboard, and means reacting to subsequent hanging up by the switchboard

  <Desc / Clms Page number 229>

 switch, to release the second powerline link and the second switchgear, as well as the first powerline link and the first switchgear.

   according to 10
24.- Telephone system, comprising means operable from the calling station of the first group via the first switchgear, for transmitting a callback signal via the first powerline link, the second switchgear and the second powerline link to the switch board.



   25.- Telephone system according to 10 and 16, comprising means acting following a response operation carried out at the called station of the first group, for transmitting a response signal to the switchboard via the second current link carrier, and other means responsive to an answering operation performed at the called station of the first group, for transmitting a response signal to the switching board via the first powerline link, the second switching apparatus and the second powerline link.



   26.- Telephone system according to 10, comprising means reacting to the state of occupation of the called station of the first group, for transmitting to the switching panel a busy signal by means of the first switching apparatus of the first current link carrier, of the second switchgear and of the second powerline link, and to transmit, in the event that the called station of the second group is in busy state, a busy signal to the switchboard from the second apparatus- switch lage via the second powerline link.

  <Desc / Clms Page number 230>

 



   27.- Telephone system according to 10, comprising means reacting to the free state of the called station of the first group, for transmitting an inrush current to the latter from the first switchgear and for sending back a return signal. 'call to the switchboard on the first switchgear, the first powerline carrier link, the second switchgear and the second carrier current link, and to transmit, following the free state of the called station of the second group, a current call to the called station, from the second switching device, and to send the return call signal to the switching panel from the second switching device, on the second float current link.



   28. - Telephone system according to 10, comprising means reacting to hanging up by the called station of the first group, for transmitting a hanging up signal to the switchboard on the first powerline link, the second switchgear and the second powerline link , and means responsive to on-hooking by the called station of the second group, for transmitting a on-hook signal to the switching panel on the second powerline link, this system further comprising means responsive to on-hooking by, the panel switch, to release the second powerline link and the second switchgear, and means responsive to release of the second switchgear to release the first powerline link and the first switchgear.



   29. - Telephone system according to 1 and 10, comprising two exchanges each provided with a switchboard, an automatic switchgear, and to which a group of lines lead, this system comprising means capable of

  <Desc / Clms Page number 231>

 be actuated from the first switchboard to enter the second switchgear on the powerline link connecting the exchanges, means which can then be actuated from the first switchboard, to control the second switchgear now entered;

   via the carrier current link, to freely route the connection to a line served by the second exchange, and means operable from the second switchboard, to enter the first switchgear on the link to powerline carrier, and then operable from the second switch board to control the first switchgear on the carrier current link, to terminate the connection to a free line of the first group.



   30.- Telephone system according to 29, in which the
 EMI231.1
 - ' <t. :: - \ !. 1. first exchange is provided with a junction circuit having an arrival channel and a departure channel, and the second exchange is provided with a junction circuit having an arrival channel and a departure channel, this system comprising means which can be actuated from the first switchboard, for entering the first junction circuit on the incoming channel in order to cause the power line switchgear provided between the exchanges to enter the second junction circuit on the outgoing channel , and means which can then be controlled from the first switch board, for selectively controlling the second switchgear with a view to passing the connection to a free line of the second group,

   and means operable from the second switchboard for selectively controlling the first switchgear with a view to passing the connection to a free line of the first group, this connection to the line of the first comprising the second powerline switchgear, the first switchgear

  <Desc / Clms Page number 232>

 with carrier current, the first junction circuit and the first switchgear seized by the first junction circuit on its outgoing channel.



   31.- Telephone system according to 1 @ 10, in which the junction circuits are connected by a junction so as to be made simultaneously free or occupied, this system comprising, in association with the first junction circuit, a first counter, means reacting to the release of the first junction circuit, to initiate the operation of the first counter, these means reacting to the occupation of the first junction circuit to release the first counter, a receiving device associated with the second junction circuit and comprising a second counter, means responsive to the release of the second junction circuit, to initiate the operation of the second counter, these means responsive to the occupation of the second junction circuit,

   to release the second counter, and means responsive to the operation of the first counter, for a first period of time, to emit a warning signal on the junction and to release the first counter and then to initiate a new operation of that -this.



   32. - Telephone system according to 31, comprising means reacting to the warning signal emitted by the first counter on the junction between the junction circuits, to release the second counter, and then to initiate a new operation of the latter, and means responsive to actuation of the second counter for a second time greater than the first time, for operating an alarm device.



   33. - Telephone system according to 31 and 32, comprising means for transmitting a start command to the second counter, these means reacting to the release of the second junction circuit, this ui has the effect of normally initiating the operation of the second counter, these mo-

  <Desc / Clms Page number 233>

 yens further reacting to the fact of the occupation of the second junction circuit, to release the second counter and means z reacting to the non-operation of the second counter after the start command has been transmitted to the latter to control the device alarm.



   34.- Telephone system according to 31 to 33, comprising the means reacting to the reception of an alarm signal on the junction between the junction circuits, to release the second counter and then to initiate a new operation of the latter, .



   35.- Telephone system according to 31 to 33, comprising a second alarm device and means responsive to the operation of the second counter for a second period of time greater than the first period of time, for activating a second alarm device.



   36. - Telephone system according to 31, in which the alarm signal is such that the means for entering the first junction and for transmitting the busy signal thereon do not react to effect the occupation of the second junction circuit , so that the latter is not seized following the sending of this alarm signal on the junction between the two junction circuits.



   37.- Telephone system according to 31, in which a prolonged busy (or seizure) signal is transmitted on the junction following the occupation of the first junction circuit, and in which, after reception of the said long signal occupancy, slow-acting means act to seize the second junction circuit, this system comprising means responsive to actuation of said first periodic signal transmitter for a first period of time, to emit a brief signal warning or alarm on the junction, and means reacting to the

  <Desc / Clms Page number 234>

 brief alarm signal, to release the second counter, and then to initiate the new operation of the latter, the slow-acting means for the release of the second counter not reacting to the brief alarm signal.



   38.- Telephone system according to 1, 4 and 10, comprising means which can be actuated from the switchboard, for transmitting successive digits to the damaging equipment on the powerline link in order to control the operation of switching stages. successive switching in the automatic switching apparatus, this system also comprising means, reacting to a determined operation requiring a period of time, of a switching stage in order to return, during this period of time; a delay signal to the switchboard on the powerline link.



   39.- Telephone system according to 38, comprising additional means responsive to the operation of a switching stage, for carrying out the occupancy test of all subsequent successive switching stages in order to send a trunk busy signal back to the junction. switch panel on powerline carrier links.



   40. - Telephone system according to 38, comprising means responsive to the operation of a final switching stage, for carrying out the occupancy test of a called line chosen by this stage, with a view to returning a busy signal. line to the switchboard on the powerline link.
 EMI234.1
 



  41.- Telephone system scloii 38e comprising, in association with the switchboard, a mechanism for transmitting digits and a signal and commands each time this mechanism is actuated, to stop the operation of the signaling device, and by which this

  <Desc / Clms Page number 235>

 device is normally actuated again at the end of each actuation of this mechanism.



   42.- Telephone system according to 41, comprising means reacting to a determined command of the dialing mechanism, requiring a period of time on the part of a switch stage, to return during this period of time a delay signal to the switch panel, andmeans reacting to this signal, to stop the operation of the signaling device of the switchboard.



   43. - Telephone system according to 38, in which several lines are accessible to the switchgear of the multistage type, and in which an end switching stage can be actuated to choose a called line from among the series of lines, this system comprising, in addition to means for carrying out the occupancy test of all the following successive switching stages, means reacting to the operation of a final switching stage, for carrying out the occupancy test of a called line, this system also comprising means reacting to the reception of the delay signal, to stop the operation of the signaling device of the switchboard, the latter means reacting to the junction busy signal or to the line busy signal,

   to activate the signaling device in one of the two characteristic ways.



   44. Telephone system according to 38, comprising additional means responsive to a callback operation performed at the called station, for returning this signal to the switching panel, and means responsive to a hang-up operation at the called station, for returning a call signal. hooking up to the switch panel, both of these signals being able to act to activate the signaling device.

  <Desc / Clms Page number 236>

 sation of the switchboard in a characteristic way.



   45.- Telephone system according to 1, 10 and 38, comprising a transmitter recorder at the switchboard, in which digits are recorded by means which can be controlled from the switchboard, this system comprising means associated with the switchboard. recorder-transmitter for transmitting successive digits to the switching apparatus in order to selectively control the operation of the successive switching stages, and means for sending a delay signal back to the switching panel when a determined operation of the transmitter requires a . delay on the part of the switching stage, the reception of the delay signal at the switching panel having the effect of stopping the transmission operation of the recorder-transmitter.



   46. - telephone system according to 45, comprising additional means reacting to a test operation for the following successive switching stages, to send a signal of busy junctions to the switching panel, and means reacting to the shutdown of the transmission of the recorder-transmitter, to transmit a junction occupancy signal to this board when the recorder-transmitter is stopped for a greater period of time than the first above-mentioned period.



   47. - Telephone system according to 45 & 46, comprising means for releasing the recorder-transmitter after all the digits recorded in it have been sent, and other means responsive to the operation of a final switching stage, for test a called line in order to return a line busy signal to the switch panel.



   48. - Telephone system according to 45, comprising means responsive to an answering operation performed at the called station to send an answer signal back to the table

  <Desc / Clms Page number 237>

 and means, responsive to the new operation of the first trunk circuit, for transmitting an on-hook signal to the first switch board.



   52. - Telephone system according to 49, comprising means which can be actuated from the second switchboard to pass the connection further, means reacting to the new operation of the first junction circuit, determined from the first switchboard 4 below. of this routing of the connection from the second switchboard, to transmit a callback signal to operate the second junction circuit from which the callback signal is transmitted to the second switchboard via the switchgear switch.



   53.- Telephone system according to 45, comprising, as part of the connection between the second junction circuit and the second switch board, a pair of line conductors, a bonding conductor and a test conductor forming a junction, means responsive to operations performed on the second switch board, to send corresponding response and on-hook signals to the test conductor, to transmit corresponding response and on-hook signals to the first board switch.



   54. - Telephone system according to 53, comprising means which normally apply a potential, determined to the test conductor when the connection is passed to the second switch board, means reacting to the response made to the second switch board, to eliminate this potential of the test conductor, these means again applying this potential to the test conductor after disconnection from the second switch board, the second junction, which contains the conductor of t is, also containing a relay

  <Desc / Clms Page number 238>

 and means, responsive to the new operation of the first trunk circuit, for transmitting an on-hook signal to the first switch board.



   52. - Telephone system according to 49, comprising means which can be actuated from the second switchboard to pass the connection further, means reacting to the new operation of the first junction circuit, determined from the first switchboard below. of this routing of the connection from the second switchboard, to transmit a callback signal to operate the second junction circuit from which the callback signal is transmitted to the second switchboard via the switchgear switch.



   53.- Telephone system according to 45, comprising, as part of the connection between the second junction circuit and the second switch board, a pair of line conductors, a bonding conductor and a test conductor forming a junction, means responsive to operations performed on the second switch board, for sending corresponding response and on-hook signals to the test conductor, for transmitting corresponding response and on-hook signals to the first switch board.



   54.- Telephone system according to 53, comprising means which normally apply a potential, determined to. test conductor when the connection is passed to the second switch board, means reacting to the response made to the second switch board, to eliminate this potential from the test conductor, these means again applying this potential to the test conductor after disconnection to the second switch board, the second junction, which contains the test conductor, also containing a relay

  <Desc / Clms Page number 239>

 working between a first and a second position following the elimination of the potential of the test conductor, in order to effect, in its second position, the return of a response signal to the second switch board,

   the return of the relay to its first position having the effect of returning the on-hook or disconnection signal on the powerline link.



   55. - Telephone system according to 45 to 54, comprising means operable from the first switchboard following the routing of the call from the second switchboard, to transmit a callback signal to the latter switchboard when this callback signal is received on the powerline link and transmitted to the second junction circuit.



   56.- Telephone system according to 1, in which the exchange fitted with automatic switchgear is connected to an office provided with a switchboard by the intermediary of a repeater connected to the exchange by a junction and connected to the office switchboard by a powerline link, this system comprising means operable from a calling station to enter the junction on the switchgear, means responsive to the occupation of the junction circuit to occupy the powerline link , and means reacting to the occupation of the powerline link, for routing the call to the central office switchboard.



   57.- Telephone system according to 56, comprising an exchange junction circuit, a source of surge battery potential in addition to the source of ordinary battery potential, the repeater having a second junction circuit provided with a potential source forwarding, and means that can be controlled from a calling station and comprising the junction circuit, the repeater, the circuit

  <Desc / Clms Page number 240>

 following junction and a symmetrical current conducting apparatus, to route a connection from a plague calling on the junction circuits and this apparatus, to the switchboard of the exchange.



   58. - Telephone system according to 57, comprising, in addition to potentials of different value within the first junction circuit, a line relay, and, in addition to the source of return potential in the first junction circuit, a signaling relay, and means responsive to the operation of the line relay for connecting the source of overvoltage battery potential to the junction between the two junction circuits, the signaling relay of the second junction circuit having a first and a second winding, the source of return potential being connected to the same junction between the two junction circuits by means of the first winding of the relay and the first device of a current conducting apparatus sy - metric,

   this device being biased to be passed through by current when the surge battery potential source is connected to the junction, so that the first winding of the signaling relay is energized, this relay being actuated to connect the return potential source at the junction via the second coil of this same relay and via the second part of the asymmetric current conducting apparatus.



   59. - Telephone system according to 58, comprising means reacting to the release of the first junction circuit, for releasing the line relay and separating the source of overvoltage potential from the junction to which the source of potential is then reconnected. ordinary battery, so that the first winding of the signaling relay of the second junction circuit is de-energized and its second winding is energized, the signaling relay

  <Desc / Clms Page number 241>

 being released after de-energization of the first winding and energization of the second winding, to disconnect the source of return potential from the junction, the signaling relay being provided with pads controlled by the activation and triggering of this relay.



   60. - Telephone system according to 58, in which, and following the energization of the line relay, the surge battery is connected to the approval translator or simplex of the two-line junction between the first and the second circuit connection, while the deflection potential is connected to the approval translator of the same junction via the first winding of the signaling relay.



   61.- Telephone system according to 58 to 60, comprising a first transformer in the first junction circuit terminating a line of this system, a second transformer in the second junction circuit terminating a second line of this system, the two-way junction lines connecting these transformers, and the overvoltage potential being applied to the simplex of the first transformer, while the source of return potential and the two parts of the unbalanced sourant conductor equipment are connected to the simple of the second transformer, and controlled means by the pads of the signaling relay to transmit control signals on the second line, while voice frequency signals are sent between the first and the second line through the transformers and the junction provided between them.



   62.- Telephone system according to 58 to 61, comprising in the first junction circuit, in addition to the line relay, a pulse relay, and comprising in the second junction circuit, a signal input relay, and a

  <Desc / Clms Page number 242>

 signal output relay, in addition to the first and second sypetric current-conducting device, the surge battery potential being connected to the junction through the coil of the pulse relay, the signal output relay of the second junction circuit being provided with a first, a second and a third coil, the latter relay being normally connected to the junction by means of the source of return potential and of the first unbalanced current conductor device,

   this system also comprising means intended, following a response to a call on the second line, to de-energize the input triais of: normally excited signals, means reacting to this de-energization to disconnect the source of return potential from with the junction and to connect this source to the junction through the first and third windings of the signal output relay and through the first unbalanced current conductor device, so as to energize the relay. pulses in series with the aforementioned last coils of the signal output relay in order to release the pulse rail, and means responsive to the release of the pulse rail for transmitting a response signal on the first lines
63.- Telephone system according to 58 to 62,

   comprising means responsive to the release of the first line of this system, to ensure the release of the line relay in order to disconnect the source of overvoltage potential by means of the first coil of the pulse relay from the junction and for connecting the source of ordinary battery potential through the second coil of the pulse relay to the junction to determine the release of the signal output relay in the second junction circuit and means responsive to the release

  <Desc / Clms Page number 243>

 signal output relay to release the second line from the system.



   64. - Telephone system according to 58 to 65, comprising means responsive to disconnection from the second line for actuating again the signal input relay of the second junction circuit in order to reconnect the potential source return to the junction via the second winding of the signal output relay and the second device of the unbalanced current-conducting switchgear, and to reconnect the source of return potential to the junction via the intermediate of the first coil of the signal output relay and of the first device, while the source of return potential is disconnected from the junction, so that the pulse relay is energized in series with the first coil of the signal output relay ,

   so that the pulse relay is made to operate again and cause the signal output relay to remain attracted to transmit a connect signal on the first line.



   65. - Telephone system according to 58 to 64, comprising means responsive to the release of the first line to trigger the line relay in order to connect the source of.), Ordinary battery potential to the junction via the intermediary a second coil of the pulse relay for the purpose of triggering the signal output relay to release the second line.



   66.- Telephone system according to 58 to 65, comprising means responsive to each release of the line relay for connecting the source of ordinary battery potential to the junction through the intermediary of the second winding of the pulse relay and for disconnecting the battery surge potential, as well., as to connect, at each re-excitation

  <Desc / Clms Page number 244>

 from the line relay, the source of, overvoltage battery potential to the junction through the first coil of the pulse relay and to disconnect the source of ordinary potential from the junction through the second coil of the pulse relay, and means responsive to the energization of the first or second coil of the pulse relay,

   to keep this relay attracted and to de-energize the first coil and energize the second coil of the signal output relay or de-energize the second coil and energize the first coil of this relay, respectively, so that said signaling relay is actuated in accordance with the line relay, to repeat the control signals on the second line.



   67. Telephone system according to 58, comprising, in the first junction circuit terminating the first line of the system, a busy relay, a pulse relay and a response relay, the busy relay being normally connected with the source of ordinary battery potential at the junction, so that the winding of this occupancy relay is normally energized by means of the second device of the apparatus which conducts an asymmetrical current,

   the occupancy relay being de-energized when the return potential source is disconnected from the pax junction via the first winding of the signal output relay and via the first unbalanced device and when the potential source relay is connected to the junction via the first and third coil of the signal output relay of the first unbalanced device, the release of the occupancy relay having the effect of establishing a connection between the potential source ordinary battery and the junction via the second winding of the

  <Desc / Clms Page number 245>

 pulse relay, for initiating a call on the first line, means reacting to the response to the call on this first line,

   to energize the response relay to disconnect the ordinary battery potential source from the junction and connect the surge battery potential source to the junction through the first coil of the pulse relay, in order to send a response signal on the second line.



   68.- Telephone system according to 1 & 8, with a first and a second exchange and a power line device connected to the line between the exchanges, each exchange serving several stations, this system comprising, in each device, tracks transmitting and receiving signaling signals and transmitting and receiving communication geese .means that can be controlled from any calling station, to make a successful connection to the first transmitting and receiving communication channel, so that the first switchgear has current bearer is made busy vis àvis other calling stations and to transmit a first carrier current on the first signaling channel.



   69.- Telephone system according to 68, comprising means reacting to the first carrier current in the second receiving signaling channel, to make the second apparatus busy with respect to second calling stations and means for transmitting a second carrier current on the second transmitting channel, and to make the first device busy with other first calling stations, following a second carrier current in the first receiving signaling channel.



     70.- Telephone system according to 68, comprising means responsive to an acoustic frequency signal coming from a first calling station, for transmitting, via the second receiving communication channel, a frequency signal

  <Desc / Clms Page number 246>

 acoustic corresponding to the second called station, and also comprising means for transmitting in response to an acoustic frequency signal from a second called station a corresponding modulated signal of the second carrier current on the second transmitting communication channel, and for transmitting , by the first receiving channel of communication, a corresponding acoustic frequency signal to the first calling station.



   71.- Telephone system according to 68 to 70, with call and monitoring signals at each switchboard comprising means which can be actuated from the first switchboard to make ¯ a connection to the first load-bearing switchgear and to thereby actuate the first monitoring signal, while the second call signal is actuated following the first carrier current in the second. receiving signaling channel.
72.- Telephone system according to 71, comprising means responsive to the connection of the second switchboard to the second transmitting and receiving communication channel, for stopping the second call signal and for transmitting a second carrier current. on the second signaling channel, and thus to stop the first monitoring signal.



   73.- Telephone system according to 68, 71 and 72, comprising means reacting to an acoustic frequency signal coming from the second switchboard, for transmitting a corresponding modulated signal of the first carrier current on the second transmitting communication channel, and means responsive to the modulated signal of the second carrier current to emit a corresponding acoustic frequency signal to the first switch board.

  <Desc / Clms Page number 247>

 



   74.- Telephone system according to 68 & 71, comprising means responsive to an acoustic frequency signal coming from the first switchboard, for transmitting a corresponding given sideband of the first carrier current, means responding to the given sideband of the first carrier current in the second - communication receiving channel for transmitting a corresponding acoustic frequency signal to the second switch board, means responsive to an acoustic frequency signal coming from the second switch board to transmit a corresponding given sideband of the second carrier current on the second transmitting communication channel and means reacting to the sideband of the second carrier current in the first receiving communication channel,

   to transmit a corresponding acoustic frequency signal to the first switch board.



   75.- Telephone system according to 68, comprising, in the first transmitting communication channel, a balanced modulator supplied by the first carrier current, for transmitting a corresponding modulated signal of the first carrier current, the second receiving communication channel comprising a balanced modulator responsive to the modulated signal of the first carrier current, the second communication transmitter path comprising a balanced modulator responsive to an acoustic frequency signal from the second switch board, while the first communication receiver path comprises a balanced demodulator supplied with the second carrier current and responsive to the modulated signal of the second carrier current, for transmitting a corresponding acoustic frequency signal to the first switch board.



   76.- Telephone system according to 68, comprising a series of power line equipment connected to the line between the exchanges, the first equipment of the first

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 switchboard being coupled in pairs with second switchgear from the second switchboard, to establish a series of channels between the switchboards, and controllable means from the first switchboard, to select any of the first switchboards for connection to the switchboard. from this table.



   77.- Telephone system according to 68, in which the first exchange is provided with an operating switchboard and the second exchange with an automatic switchgear, this system comprising means which can be actuated from the switchboard. , to emit pulses of the first carrier current corresponding to the different digits by means of the first emitting signaling voice and the means corresponding to these pulses of the first carrier current and provided in the second receiving channel, to selectively actuate the switchgear in order to terminate the call at a called subscriber station.



   78.- Telephone system according to 76 & 77, comprising means responsive to the response to the call at the called subscriber station, for routing a connection to the second transmitting and receiving communication channel, by emitting a second carrier current on the second signaling emitting channel, and means responsive to the second carrier current and provided in the first signaling receiving channel, for returning a response monitoring signal to the switch board.



   79.- Telephone system according to 6 & 76, comprising means provided in the switchgear and intended to carry out the test (free or busy) of the called subscriber station and to return the acoustic frequency busy signal to the switchboard in the event that the called subscriber is busy, the so-called busy buzzing

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 being transmitted on the second communication transmission path, which transmits a corresponding signal modulated from the first carrier current to the first communication receiver path to transmit a corresponding acoustic frequency signal to the switch board.



   80.- Telephone system according to 76 to 79, comprising means reacting to the disconnection of the switchboard from the first transmitting and receiving communication channel, for interrupting transmission on the transmitting signaling channel and means responding to interruption of the first carrier current in the second signal receiving channel, to release the switchgear.



   8 1.- Telephone system according to 76, comprising means reacting to the initiation of a call in a calling subscriber station, to connect this station to the switchgear, means reacting to a digit formed at the telephone station. calling subscriber, to actuate the switching apparatus in order to route the connection to the second communication transmitting and receiving channels, means reacting to this connection, for transmitting a second carrier current on the second signal transmitting channel, means responsive to the second carrier current in the first receiving channel, to transmit a monitoring call to the operator's table, and means responsive to the response given to this call by the operator's board,

   to route a connection to the first sending and receiving channel
82.- Telephone system according to 76 & 81, comprising means responsive to the first carrier current in the second signal receiving path, for reversing the polarity of the connection to the calling station.



   83.- Telephone system according to 76 & 82 comprising means reacting to the disconnection of the call to the switchboard, to interrupt the transmission of the first connection.

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 carrier on the first signal transmitting channel, and means responsive to the interruption of the first carrier current in the second signal receiving channel, for reestablishing the polarity of the connection terminating at said calling subscriber station.



   84.- Telephone system according to 6 and 81 to 83, comprising means reacting to the disconnection of the call in the calling subscriber station, for interrupting the transmission of the second carrier current on the second signal transmitting channel, and means reacting to the interruption of this second carrier current in the first signal receiving channel, for sending the cut-off monitoring signal back to the switchboard.



   85.- Telephone system according to 68, in which the first and the second exchange each comprise an automatic switchgear, comprising means responsive to the initiation of a call in a calling subscriber station, for connecting this station to the first apparatus switch in order to actuate this apparatus by forming a number, in order to route the connection to the first communication sending and receiving channel, means reacting to the first carrier current in the second signal receiving channel, to enter the second switchgear, means responsive to the formation of another digit at the calling subscriber station for transmitting pulses on the first signal emitting channel,

   and means responsive to these pulses of the first carrier current in the second signal receiving path, for selectively actuating the second switchgear, to route the call to a called subscriber station.



   86. - Telephone system according to 85, comprising means reacting to the answer of the call in the subscriber station

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 called, to establish a connection to the second transmitting and receiving communication channel, and for transmitting X a second carrier current on the second signal transmitting channel, and means responsive to the second carrier current in the first signal receiving channel, to reverse the polarity of said connection terminating at the calling subscriber station.



   87.- Telephone system according to 85 and 86 comprising means reacting to an acoustic frequency signal coming from a calling subscriber station, for transmitting a corresponding modulated signal on the first transmitting channel of communication to the second receiving channel of communication and to the second called subscriber station, and means responsive to an acoustic frequency signal from the second called subscriber station, for transmitting a corresponding modulated signal of the second carrier current on the second transmitting communication channel to the first communication receiving channel for transmission of a corresponding acoustic frequency signal to the first calling subscriber station.



   88. Telephone system according to 85 to 87, comprising means in the second switching apparatus for carrying out the test - (free or busy) - of the called subscriber station, in order to return an acoustic frequency busy signal to the second channel communication transmitter in the event that the called subscriber station is busy, means reacting to the acoustic frequency signal in the second communication transmitter channel, for transmitting a corresponding modulated signal from the second carrier to the first communication receiver channel , in order to transmit a corresponding acoustic frequency signal to the first calling station.



   89.- Telephone system according to 85 to 88, comprising means reacting to the cut-off of the communication in the calling subscriber station, for releasing the first switchgear and thus for interrupting the transmission of the first.

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 The first carrier current on the first signal-transmitting channel, and Its means, responsive to the interruption of the first carrier current in the second signal-receiving channel, to release the second switchgear.



   90. Telephone system. substantially as described and as shown and for the purpose set forth above.