BE420586A - - Google Patents

Description

       

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  Improvements to telephone systems.



   The present invention relates to telephony systems, it relates more particularly to those in which automatic switching devices located in a central telephone office are remotely controlled by the operator serving a remote central office, the control being exercised by the operator. Intermediate what is commonly called a control junction circuit.



   The most general object of the invention is to provide new and improved circuits which give the possibility of establishing more rapidly the communications emanating from a remote controlled automatic office, at the same time.

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 that it provide a service that is simpler than that which has hitherto been possible with offices of this kind.



   A specific object of the invention is to provide a new arrangement allowing the use of two control trunk circuits alternately to pass calls through the same group of automatic switches, thereby making it possible to establish simultaneous communications more quickly. in the remote controlled office.

   The operation of the above arrangement is further dependent on each of the control junction circuits being associated with common control equipment which can be put into service to replace any automatic switch to which the control junction circuit is connected, It seems this is the first time that two or more common control equipments have been provided for common use of the same group of automatic switches.



   In the arrangement shown, the remotely controlled office is located in relation to two offices served by an operator so that the remote control of the establishment of calls is exercised by one of the offices and that long-distance communications, both at home. '' arrival that at the departure of the remote-controlled office, are passed for the greater part by the other office,
The invention is described with reference to one of its applications shown in the accompanying drawings, among which FIG. 1 shows the layout plan of the remote-controlled office and of two neighboring offices; Fig. 2 is a junction diagram showing the relationship between the different groups of equipment in the remote controlled office; Fig. 3 to 20 are circuits;

   and fig. 21 watch

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 how the plans should be juxtaposed to form a whole.



   With particular reference to FIG. 1 we can see that the three offices are interconnected by junction circuits and 'that they are designated by the letters A, B and C.



    Office B is the remote controlled office; office A is located relatively close to office B; it is for this reason that the local traffic of office B is placed under the control of office A. Office C is the one from which long distance communications, both outbound and inbound, are controlled unless these communications should not be directed to office A as a result of the destination or origin of the call.



   Two trunk circuits are provided between offices a A and B, OT1 and OT2 respectively. The fact that there are only two trunk circuits is indicated by the number 2 placed in a circle next to the trunk circuits. Four local service trunks are provided, they are operated in both directions, and marked with the letters LST and the number 4 placed in a circle, For the flow of long-distance communications which can be brought from other neighboring offices to through office A (not shown)

   and destined for office B, an interurban line TL1 was established. This line can also be used for the flow of calls made by office B through office A and destined for other offices which can be reached more easily through office A than through office C.



   The TL2 trunk line is part of a group of 4 lines operated in both directions for the flow of traffic between offices B and C, and between office B and all other offices that can be reached through the office. VS; the TL3 trunk line is a junction that is part of a /

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 group connecting offices A and C with the aim of providing direct intercity connections between these two offices.



   Offices A and B are located sufficiently close to each other for the tariff applied for communications between these two offices to be the same as that in force for local communications in each of these networks. This is the reason why trunk circuits for local service, such as LST, which serve to carry traffic between the two offices, and separate from the junctions carrying long-distance traffic which can be directed from one of the offices, have been provided. towards the other.



     Referring now particularly to the. fig. 2 we will explain what the equipment of the remote controlled office B consists of:
Local traffic is carried through connection circuits comprising a finder and a connector, one of which comprises the finder F and the connector for local service LOC. The connection circuit shown is one of the 7 identical circuits as shown by the number 7 placed in a circle above the finder F.



   Finder F has access to local line call pins through line circuits such as LC1 through LC3, local connector LOC has access to line response pins which are common to local connectors and connectors long distance such as TC1 and TC2.



   One of the characteristics of the system exposed here is that the same group of connectors serves lines with 4 grouped stations with total selection and lines with 10 grouped stations with call by code.The F'PL line represents lines with 4 grouped stations with selection total and the TPL line represents the line with 10 grouped stations and call by code. These soft lines end in the level at the line circuits LC1 and LC2 respectively.

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 It is also possible to serve lines to a single station, preferably by equipping this line with a bell connected between the two wires and by using one of the 10 codes to ring this station when it is called.



   The trunk circuit for local service LST (fig, 1 and 2) represents one of the four trunk circuits which connect the offices A and B. This trunk circuit ends in the office B to the line circuit CL3, this one is similar to line circuits LC1 and LC2. Local calls between offices A and B therefore flow through the local connection circuits of office B in the same way as local calls from this office.



   In order to allow the use of prepaid stations, separate lines, such as the PSL line of the 1600 prepaid station, have been planned. This line is connected to the LC4 line circuit which is different from the LC1 to LC3 line circuits in that it is not accessible to local researchers, but is provided with an LS preselector which searches for an access to the four trunk circuits for local service, LST. As a result, a call from a prepaid station is extended through a trunk for local service to office A assuming that most calls from prepaid stations are intended for office A or to another field office.

   In the rather rare case where from a prepaid set a subscriber of office B is called, the operator of office A can forward the call to office B through another trunk circuit for local service LST. Apart from when an inter-city call is taken from a prepaid station, the operator in office A extends the connection via an inter-city line such as the TL3 line in fig, 1, up to the interurban operator from office C, she takes note of the

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 requests and later recalls the prepaid set via an interurban line, such as TL2 connecting offices B and C of fig. 1 and 2, when the connection is established.



   In order to control researchers such as the, the preselection distributor D of FIG. 2 sought access to all researchers. The ST starter wire runs from line circuits such as LC1-LC3 to distributor D for the latter to control a preselected seeker which searches for the calling line when a call is made.



   The control circuits OT1 and OT2 terminate in the common equipment units CE1 and CES respectively. The control wires associated with these two units are multiple in each of the local connectors, such as LOC, to allow each of the local connectors to be associated with any one of the common equipment units and with the control circuit to which it is connected. it is connected. The arrangement (which will be described in detail later) is such that the control circuit OT1 is normally put into service when they are both free, and the control circuit OT2 is put into service in the event that a second call is made. occurs when the control circuit 0 'is already occupied.

   By this arrangement, the calling subscribers do not have to wait so long before getting an answer when the calls follow one another rapidly.



   Each of the interurban lines such as TL1 and TL2 in Figs. 1 and 2 results in a trunk connector such as the connector TC1 and TC2 of fig. 2, each of the interurban lines passing through the contacts of a transfer relay of one of the outgoing junction circuits such as OTC1 and OTC2. These outgoing junction circuits are interposed between the pins of the connector banks carrying outgoing trunk communications and the trunk line itself.

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 for monitoring and controlling supervision and calling.



   In the case of a remotely controlled office of the type in question here, provision is usually made for a junction, which may be used normally used for other services, / as a control junction circuit if necessary, for example, after a storm that would have cut the normal control junction.



  As two control trunks are provided in the system discussed here, all calls can be temporarily passed through / through trunk circuits in the event the other becomes faulty. For this purpose connections are made between the units of the common equipment and of the wires coming from determined contacts of the connector banks so that the operator of one of the offices A or C can send a determined number to any of the connectors and cause occupancy any of the common equipment units and its associated control trunk so that no further calls will be directed to the faulty trunk circuit.

   Subsequently, a determined but different number can be transmitted to make the control junction circuit free after repairs have been made.



   In the event that the two control junction circuits become defective, relay 856 of fig. 2 can attract and transfer control, ordinarily exercised through trunk circuit OT1, to the trunk line TL2 which connects offices B and C, so that calls from office B can be routed through office C using the TL2 trunk junction temporarily as a control junction circuit.

   The reason for placing the operation of the remote office under the control of office C instead of transferring it to another trunk circuit terminating at office A is based on the fact that in the present case there is has a high probability that the fault is

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 general and that the other lines connecting offices A and B are also defective. This can happen, for example, when a post is knocked down. The relay 856 attracts to carry out this transfer under the action of sending a determined number to any of the connectors of the office B, as indicated by the connection connecting this relay to the wires coming from the banks of the connectors .

   The transfer relay can then release under the action of sending a second determined digit to any of the connectors.



   Provision has been made in the system which is disclosed here that a person having received a special authorization will be able to locally control the operation of a remote controlled office by means of the LCS local control device, for example in case of necessity when none of the circuits junction cannot be used.



   The local arrangement shown in FIG. 2 having been described, attention will now be drawn to the general aspects of the circuits shown in FIGS. 3 to 20, in which the circuits of the apparatuses of FIG. 2 and some equipment mounted in offices A and C are shown in detail. As it was said previously the figs: 3 to 19 must be assembled as shown in fig. 21. The equipment shown in fig. 3 to 11 and 16 to 20 is located in office B, the equipment shown in figs 12 and 13 is located in office A finally the equipment shown in figs, 14 and 15 is located in office C.



   Figures 3, 4 and 5 show the line circuits LC1, LC2 and LC3 respectively, they are all identical and associated respectively with the FPL line with four grouped stations, with the TPL line with 10 grouped stations and with the local trunk LST . Figures 3, 4 and 5 also show the terminal pins of researchers 351, 451 and 551. Through these pins

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 and their multiples, the researchers establish the connection to the calling lines. Figs. 3, 4 and 5 also show pins 350, 450 and 550 of the connectors. Through these pins and their multiples the connectors establish the connection with the lines in question when called.



  Note that the wires from the LST junction circuit are reversed at the negative and positive pins of group 550 and their multiples to give supervision to office A as will be explained later.



   Starter leads 361, 461, and 561 go to the appropriate starter leads associated with starter relay 801 of fig. 9. Each of the starter wires 361, 461 and 561 (as well as each of the 7 other starter wires associated with groups of line circuits not shown) is multiplied to the 10 line circuits reached via a determined bench level of, = researchers as is normally done.



   The wires 6, 7 and 8 represent the finder F1 and the local connector LOC which is associated with it and which are connected by the junction wires 621-626. The seeker bench is not shown except for pins 351, 451 and 551 connected to the line circuits of Figs. 3, 4 and 5. It will in fact be understood that there are 100 groups of pins such as this one in the researcher bench and that these pins are connected in multiple with the corresponding pins of the other researchers.



   The bench of the LOC connector in fig. 8 is not shown with the exception of pins such as 350, 450 and 550 which are associated with the line circuits of FIGS. 3, 4 and 5. It will in fact be understood that the bank of the LOC connector is a 00-pin bank having 100 groups of pins such as those shown in FIGS. 3, 4 and 5, these pins are connected in

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 multiple to the bank pins of the other connectors in the usual way which is well known. Note that the brushes 700 of the local LOC connector are marked negative, positive, C and EC respectively. The pins of FIGS. 3, 4 and 5.

   From the above it can be seen that no connection is closed through the brush EC of the local connector LOC when a line such as that shown in fig. 5, 4 or 5 is called. The EC pin is only used in the case where a trunk line is called through pins such as 1450 in fig. 16 whose EC pin is connected to the circuit via the forced release wire 1422.



   The LOC connector in fig. 7 and 8 is provided with a group set selector PS1 which selects a set from a group when called. This grouped station selector has brushes 741 and 742, each of them has a double bank of contacts arranged such that they are bridged in pairs depending on the position taken by the brush. The brushes are brought into position under the action of the electromagnet 743, they are returned to the rest position under the action of the release electromagnet 744.



   Fig. 9 shows the distributor D which is composed of a group of relays and the rotary switch comprising the brushes 821-825 driven by the electromagnet 800. FIG. 9 also shows a group @G of miscellaneous relays including relays 851-856. The relays of this group are used for various purposes which will be specified in the course of the description.



   Figs. 10 and 11 represent the IEC and CE2 common equipment units. The common equipment IEC unit is shown in detail, while the common equipment CE2 unit only certain pins have been shown as well as the

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 wires that connect to it. Certain terminals of group 900 appearing in the left corner of fig. 10 are not used in unit CE2 and are therefore not represented in group 900 'associated with common equipment CE2. These terminals specific to CE1 have been identified by a line surrounding them such as, for example, the 5 terminals of group 900 associated with the supervision switch SS.

   It is preferred, however, for uniformity of construction that the two units of common equipment be of exactly similar manufacture. In this way, the two units are interchangeable and certain parts of the common equipment CE2 are only necessary when this takes the place of the common equipment CE1.



   The control junction circuit OT1 shown extends from the unit CE1 of the common equipment of FIGS. 10 and 11 through the upper part of fig. 9 up to the control equipment of FIG. 12 located in office A. The control junction circuit OT2, associated with CE2, is equipped in the same way.



   Fig. 13 represents the jack and the equipment of the junction circuit of office A associated with the LST circuit for local service. Each of the three local service trunk circuits discussed below '' is; equipped in the same way.



   Fig. 14 shows the junction circuit jack and equipment at the trunk position located in office C and associated with the TL2 trunk line operated in. both ways. Fig. 14 also shows the KS transfer key used to transfer the TL2 trunk line from the jack and the junction circuit equipment of fig. 14 to the control equipment of FIG. 15 when the interurban line TL2 is to be used temporarily as a control junction circuit.

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   Fig. 15 shows the control equipment put into service when the trunk line TL2 is used as a control junction circuit and the control equipment of which is similar to that shown in FIG. 12 and used at desk A to exercise control through control junction circuit OT1.



   Fig. 16 shows the outgoing trunk circuit OTC, associated with the trunk line TL2, through which outgoing calls to the trunk line are made.



  This outgoing junction circuit is accessible to local connectors via pins 1450 and their multiples, and to long distance connectors via terminals 1451 and their multiples. This junction circuit includes transfer relay 1411 which substitutes the outgoing trunk circuit OTC for the trunk connector TCC when. the OTC junction circuit is put into service.



   The intercity connector TC2 in fig. 17 and 18 is used to establish communications entering office B and coming from office C. This trunk connector, as well as the local connectors of FIGS. 7 and 8, is provided with a group station selector designated by the letters PS2.



   The invention having been described in general, a detailed description of the operation of the system will be given below.



   We will first explain how a local call is established to a line with 10 grouped stations with call by code. For this purpose, it will be assumed that the subscriber of set 300 of the FPL line with 4 grouped stations wishes to contact the subscriber of station 40C connected to the line with 10 grouped TPL stations.

   To obtain the desired communication, the subscriber of set 300 picks up his receiver and waits for the

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 the operator answers, when she answers he lets her know the number requested, the operator establishes the desired connection and rings the called subscriber. when you pick up the receiver (not shown) at station 300 the closing of the DC bridge at the terminals of the FPL line wires has the effect of attracting the line relay 301 connected to the terminals of the line wires in series with the battery of the central office and the contacts of the cut-off relay 302.

   The relay 501 attracts and places, at its lower contact, a positive on the starting wire 361; it disconnects pin C of group 350 from relay 302 and connects it to the positive, so as to immediately protect the calling line against any seizure by one of the connectors, it connects the coil of relay 302 through contacts from relay 303 to pin C of group 351 to mark this group of pins as calling, in the bench of researcher F1 and other researchers.



   It will be assumed that the call is made at a time when the CEI and CE2 common equipment units are ure and the other free, and at a time when the brushes 821-825 of distributor D of fig. 9 are engaged on the pins of the wires 831-835 leading to the finder F1 of FIG. 6. Since the CEI and CE2 common equipment units of fig. 10 and 11 are free a negative is maintained at the lower terminal of relay 801.



   Connecting a ground to wire 361 closes the circuit of relay 801 through the corresponding wire of the group of starting wires of fig. 8 and through resistance.



  When relay 801 pulls it closes the circuit of relay 802 through the normally grounded wire 861.



  The switching relay 802 attracts in series with the control solenoid 800, but the latter does not attract because

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 of the relatively high resistance of relay 802. The relay 802 closes its own blocking circuit at its lower contact without the back-up of the contacts of the starting relay 801, in addition to putting the finder F1 into service as will be shown. later. Switch relay 802 also closes, at its lower contact and through the contacts of relay 808, the circuit of relay 806 of the relay group 806-808 comprising a timing starter.

   These three relays cooperate to limit the search time and to switch on a second finder if the first one fails to find the calling line within a short interval, 3 seconds, for example. The relay 806 attracts under the action of its upper winding to open the initial supply circuit of the relata 802, to prepare the blocking circuits of the relays 804 and 805 through their lower windings, and to attract the relay 807 under the action of its lower winding. Relay 807 closes the circuit of relay 808 and the blocking circuit of relay 806 through its lower winding.

   Relay 808 pulls in and locks on itself through the lower contacts of relay 802, it cuts the circuit of the upper coil of relay 806 and the circuit of the pendulum relay 807. Relay 807 immediately releases and allows its weighted spring to vibrate. The circuit of the lower winding of relay 806 is cut momentarily at each extension but the relay 806 being delayed on release remains attracted until the oscillations are sufficiently attenuated, at the end of several seconds for example, this time being normal. - sufficient to allow a researcher to complete a complete cycle.



     @n returning to the operation of relay 802, we see that an inversion circuit is prepared at its upper contact

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 inside, it borrows the upper winding of relay 804 and the control brush; the upper winding circuit of relay 805 closes, the circuit of the control solenoid 800 closes through contacts of relays 806 and 808; the test brush 821 is disconnected from one side of the switch contacts associated with the control electromagnet 800 and is connected directly to the electromagnet;

   an earth is extended to its upper contact through contacts of relays 803, 806 and 804, the brush 824, the vertical wire 834 up to the ascent electromagnet 603 of the researcher F1, finally an earth is placed on starter wire 855 through contacts of relay 805 and brush 825.



   Relay 602 draws through wire 835 and connects wire 836 through contacts of relay 601 to rotational solenoid 604; it connects the common selector wires 961 and 962 to the individual selector wires 625 and 626; it removes the positive of wire 861 at one point, it disconnects test wire 831 from shaft contacts 607 and prepares an automatic return circuit through contacts 608, to its upper contacts it applies a ground to the point junction of the two windings of the selection relay 601 electrically polarized which causes the sending of a current in the lower winding or polarization winding of this relay and prepares a test circuit through the upper winding of the relay through brush C to allow the finder to test the calling line in the marked pin group.



   The ascending electromagnet operates as a result of closing its circuit through wire 834 and raises its brushes 600 and 609 by one step. It also applies a ground to the control wire 832, which closes the circuit of relay 803 through brush 822. Relay 803 attracts and interrupts.

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 the ascension electromagnet circuit 803, thereby the ascending electromagnet 603 releases and opens the circuit of relay 803 which releases and again closes the ascension electromagnet circuit . This action continues until the brushes 600 and 609 have been brought in front of the level of the bank contacts containing the calling line.



   When the level of the bank contacts containing the calling line is reached, the test brush 609 encounters a ground through a multiple of the corresponding level starter wire of FIG. 9. This causes the attraction of the relay 804 (through the wire 833 and the brush 823) the attraction being brought about by the supply of the upper winding of the relay 804 through the internal upper contacts of the relay 802. The relay 803 remains attracted in series with the relay 804 until the latter attracts.

   When relay 804 attracts (this operation being slightly delayed by the action of the copper ring placed on the side of the armature as indicated by the black rectangle at the top of the relay) it locks itself on contact. lower interior and through the contacts of relay 806; it disconnects brush 823 from its upper winding and connects it through the contacts of relay 802 to the upper winding of relay 805. Relay 805 is not attracting at this time although the upper terminal of its upper winding is connected to the positive through contacts of relay 802, because the positive is connected to both terminals of this winding.

   At its upper contact, relay 804 transfers the control circuit of the ascent solenoid 603 to the common rotation control wire 836, it passes through contacts of the individual relay 602 of the researcher F1 and the contacts of the relay switch 601 to terminate 4 the searcher rotation electromagnet 604. Therefore when the relay 805 releases as a result of the attraction of the relay 604 the circuit of the rotation electromagnet 604 closes.

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   The rotation electromagnet 604 attracts the relay 603 through its contacts as has been described for the ascending electromagnet 603. As a result, the brush 609 is disengaged from contact with the. vertical test bench 610, and that the brushes 600 travel through the contacts of the calling level until they reach the terminals 351. The brush 6000 tests each of the C pins with which it comes into contact, but the C pins Line circuits encountered by the finder brush C are normally disconnected from the line circuit.



   When the LOI line circuit is reached, a characteristic inrush polarity is encountered by searcher F1 brush 600C through relay 302, the upper contacts of relay 301 and contacts of relay 303. As a result, Current flows through the top contacts of relay 602, the top winding or test winding of electrically biased switching relay 601, in series with relay 302 of the LOI line circuit.

   When the relay 601 attracts, it opens the circuit of the rotation electromagnet, it opens at another point the circuit of the release electromagnet 605; it closes the circuit of the conversation wires 621 and 622; it connects finder brush C, the end of its own winding, and ground wire 623 together to provide a clean blocking circuit and to place a ground directly on wire C terminating at the LOI line circuit. The blocking wire 623 is normally grounded in the local LOC connector in fig. 7 via contacts of relay 708 and contacts of relays 702 'and 702.

   As a result, relay 602 is not able to remain attracted by the action of its lower biasing and blocking winding after relay 602 has released as it does shortly thereafter.

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   When the LC1 line circuit is found, the relay 302 draws in series with the finder relay 601, it is blocked directly to the lead C of the associated finder by the intermediary of its internal upper contacts; it disconnects the relay 301 and the positive of the FPL calling line wires, at its lower contact it closes the circuit of the relay 303 which attracts and prepares the faulting of the FPL line in the event that it becomes defective, this operation will be described in the course of the description. With relay 301 released and relay 303 pulled, ground is removed from starter wire 361 allowing relay 861 to release unless another call has been made within this time.

   It should be noted that the release of the relay 801 has no immediate effect on the rest of the operations of the distributor D because the relay 802 was blocked during this time at its lower internal contact as it was said previously and for the additional reason that the positive has been removed for relays 804 and 806 when contacting relay 801.



   In the local LOC connector, relay 706 now draws into the calling line circuit to attract relay 707. Relay 707 additionally grounds blocking wire 623.



   In the Fl researcher, the relay 601 at its lower contact transfers the rotation electromagnet 604 of the wire 836 to the control wire 833 which extends a negative polarity through this wire, the brush 823, the contacts of the relay. 804 attracted, the contacts of relay 802 attracted to relay 805.



  Relay 805 attracts and is blocked by means of its lower internal contacts to the positive taken at the lower contact of relay 806. At another contact, relay 805 cuts the circuit established previously to supply relay 835 through wire 835, to his inner superior contact he closes

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 the circuit passing through the contacts of relay 901 of the common equipment CE1 and of the wire 961 (associated with the common equipment CE1) to cause the socket of the common equipment CEI by the local connector LOC connected to the finder Fl of the fig. 6. This circuit passes through contacts of relay 602.

   Although the relay circuit is cut by relay 805 when the tap circuit closes, this circuit remains closed for a sufficient time to allow taping because the relay 602 is delayed by the effect of the ring which surrounds its core. Note that the "plug" polarity is placed on the selection wire 961 because the relay 901 of the common equipment CE1 is released which indicates that the control equipment is free, but if this relay is attracted. and that the common control equipment CE2 is free, the tap pulse is transmitted on the selection wire 962 associated with the common equipment CE2.



   When relay 602 releases when relay 805 breaks its circuit it disconnects common wires 856, 961 and 962 from the individual wires associated with them, it prepares the circuit for release solenoid 605 (which is open at relay 601 ) through the actuated shaft springs 606, it places an earth on the test lead 831, through the actuated shaft springs 607, so that the finder Fl is found busy when tested by the distributor D and so that the researcher is therefore protected from any subsequent capture until he is free again.



   In distributor D when the positive is placed on test lead 863 the circuit of the control electromagnet 800 closes through the brush 821 and the contacts of the drawn relay 802 of the distributor. The electromagnet 800 attracts when this circuit is closed but as we know the brushes 821-825 do not advance until the electromagnet has released.



  The electromagnet does not release until the relay

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 802 releases because it is short-circuited by closing the power supply circuit of the drive solenoid 800 and its circuit is cut when the solenoid 800 attracts and opens its switch contacts.



   When relay 802 releases the grounded brush 821 is transferred from its direct connection to the drive solenoid 800 to its normal connection through the switch contacts of the solenoid. The electromagnet 800 therefore releases and advances the brushes 821-825 by one step; at the same time it closes its switch contacts to allow a subsequent automatic advance of the brushes until the brush 821 encounters a test contact which is not connected to earth which indicates that the finder is free.



   When the switching relay 802 releases, the blocking circuit of the lower winding of the blocking relay 806 is cut off. Relay 806 releases after a very short time allowing relays 804 and 805 to release when their blocking circuit is open at the lower inner contacts of relay 806. Relay 808 is also unblocked at the lower contacts of relay 802.

   When these relays are released, distributor D has completed a complete cycle of normal opera- tions and is ready to be put back into service to control the operation of the next searcher which will be selected, since an earth is given. back to contact 801 through wire 831 through contacts on relays 808, 806 and 804, so relay 801 can control relay 802 again when the opportunity arises.



   It may happen that a finder becomes defective, either mechanically or electrically, so that it no longer functions properly to find the calling line. In this case the time starter, made up of relays 806-808 operates so that the distributor D selects a

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 another searcher who goes to find the calling line.



  This function will be explained below:
It will be remembered that the relays 806, 807 and 808 successively attract as a result of the attraction of the relay 802, that the relay 808 is blocked when it has attracted and that when the relay 807 releases the ballasted contact vibrates and maintains the relay 806 attracted. When this weighted contact vibrates with force the lower winding circuit of relay 806 remains closed almost continuously, relay 806 remains attracted because it is delayed on release. However, when the vibration of the ballasted contact is attenuated and if it is assumed that the searcher has not found the calling line and has not allowed the release of the distributor, the relay 806 releases.

   Relay 806 removes the positive from the ballasted contacts at its lower internal contact, at the same time it opens the blocking circuit of relays 804 and 805 (if we admit that these relays have attracted). Likewise, relay 806 closes the circuit of the control electromagnet 800 at its upper middle contact by means of the positive taken from the contacts of relay 802 through the contacts of relay 808. Closing of this circuit short-circuits relay 802. The electromagnet 800 now attracts to prepare the advance of the brushes 821-825 at the same time as the disconnection of the relay 802 to its switch contacts. Relay 802 releases, at its lower contact it opens the circuit of relay 808 and the circuit of the control electromagnet 800. The control electromagnet 800 releases and advances the brushes 821-825 by one step. .

   Since the relay 802 is released, the brush 821 is reconnected, in the usual search circuit, to the electromagnet 800, the latter therefore operates like a buzzer and searches for a free searcher, the relay 802 remaining released until that a free finder is found.

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   When the relay 808 releases, the earth is reconnected to the contact of the relay 801, it follows that the relay 802 can attract again as soon as the brushes 821-825 have been associated with another free seeker.



   Note that the time starter operates to allow distributor D to restart its cycle of operations and to advance at any time if the switching relay 802 does not release in the usual way, when a starting relay releases (such as finder F1 relay 602) and when a guard positive is applied to the test lead (such as lead 831), within the time allowed for the starter to activate. In this way, the operational safety of the system is greatly increased and the advance of the distributor D after the establishment of each connection through a finder is ensured in a more efficient manner.



   Occasionally a searcher cannot find the calling line. This can happen in the event that brush 609 momentarily makes faulty contact with the bench pin, in the event that one of the multiple wires connected to the vertical test bench 600 is disconnected, or when the caller hangs up his receiver. after the departure of the researcher and before he arrived on the contacts of his line. The seeker can stop in front of any level and turn to the end of it, or he can not stop and go up to the tenth level.

   It will be observed that the tenth level contact of the researchers of bench 610 is permanently connected to the earth to ensure that the brush 609 will always meet a positive when it reaches the extreme position of its stroke, therefore when the researcher turns in a level and passes the last contact of his bench the contacts 600 of surplus close. Closing these contacts, the relay

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 start being attracted results in a positive being applied to test lead 831 which starts the cycle of dispenser operations again as stated above, so it advances to the next free seeker. The faulty seeker which has been brought to the extreme position is returned to the normal position when it is released by the distributor.



   The way in which IEC common equipment is entered will be explained below. when the turn-on pulse is sent, as previously explained, to the individual number 1 selector wire 625 at the connector of fig. 7 the selection relay 701 attracts to close its own blocking circuit and to apply to wire 625 an additional earth taken from wire 623. To its upper middle contact, relay 701 connects the earthed ground wire 623 to wire 734 to prepare the blocking circuit of certain connector relays, at its lower contact it disconnects the connection relay 703 'to prevent any attraction of this relay at this time.



   In addition to the inner upper contacts of 'selector relay 701, the circuit of relay 703 closes through contacts of relays 702 and 702'. Relay 703 draws and connects the wires of the cable C1, which runs between the common equipment unit CE1 and the various local connectors, to the local connector LOC making the unit CE1 common equipment temporarily individual to the local LOC connector.



   By connecting wire 957 of the CI cable to the rotation solenoid 717 of the local connector LOC the circuit of the relay 908 of the common equipment IEC closes through the rotation solenoid 717. , wire 757 and contacts of relay 923. Relay 908 attracts in this circuit but the rotation solenoid 717 does not attract due to the high resistance of relay 908.

   Relay 908 places an earth

  <Desc / Clms Page number 24>

 on wire 930, which crosses the circuit of relay 901 through contacts of relay 805 (as soon as the latter releases when releasing the distributor), The attraction of relay 901 is delayed, until the relay 805 releases, in an effort to prevent premature transfer of "plug" ground from ± 61 wire to 962 wire of the second common equipment unit.



  Relay 901 closes its blocking circuit at its lower contact inside wire 930, at its lower contact it overrides a polarity connected to the lower terminal of relay 801, so that when the two units of common equipment are in service, relay 801 cannot cause the dispenser to operate unexpectedly.



   Relay 908 also connects the start and "tap" wires 11 931 and 932 of the T time device to the response time device comprised of relays 909-911. The purpose of this operation is to allow relays 909-911 to operate in conjunction with the device in time T to send an alarm on wire 949 in the event that the call is not answered within a period of time. determined. A further discussion of this function is given later.



   When attracting, relay 908 closes the circuit of relay 906, at its inner lower contact through contacts of relay 907. Relay 906 thereby causes relay 907 to pull. Relay 907 attracts and locks directly to the lower inner contacts of start relay 908, at the same time it disconnects relay 906 and allows it to release. During the time that the relay 906 is attracted, the upper wire of the OT1 circuit is open to the contacts of the relay 906, this opening, is only momentary and ends as soon as the relays 906 and 907 have operated. The interruption in the upper wire of the control junction circuit is provided to give a signal to the operator of control office A.

  <Desc / Clms Page number 25>

 



   It will be noted that the two windings of the relay 913, in series with the windings of the differential relay 912 and the left windings of the translating coil 947 are placed at the terminals of the wires of the OT1 junction circuit in series with the battery supplying the office. It will also be observed that the upper winding of the line relay 1003 of fig, 12 is connected to the terminals of the wires of the junction circuit OT1 to the office A in series with an element of high resistance, via the contacts of the relays connection 1006 and 1006 'and the straight windings of the translating coil 1002.



  Relay 1003 is normally attracted but the amount of current flowing through the line is limited by the coil of the relay and the resistance element so that the line relay 913 at the remote controlled office is not normally attracted. When the upper wire of the control junction circuit is momentarily interrupted by the operation of relay 906 of the common equipment unit, relay 1003 momentarily releases and closes the circuit of relay 1004.



  Relay 1004 locks to ground taken through contacts of relay 1005 such that it remains pulled when relay 1003 has pulled back at the end of sending the signal produced in the remote controlled office.



   When the relay 1004 attracts, at its upper contacts it closes the supply circuit of the lamp 1007 to draw the attention of the operators of positions 1 and 2 in office A to the fact that a call has been made on the circuit of OT1 junction.



  One of these operators is provided with the equipment 1000, and the call device 1001, the other has the equipment 1000 'and the call device 1001'. The answer key K1 is a two-position key mounted so as to be able to be operated by the two operators, any one of them being able to manipulate this key to answer a call. when the operator in position 1 answers the call

  <Desc / Clms Page number 26>

 the key is lowered to the left, when the operator in position 2 responds, the key must be lowered to the right. Relay 1006 attracts in the first case, relay 1006 'in the second.



   Assuming now that the operator in position 1 answers the call, operation of relay 1006 has the effect of disconnecting the wires of the OT1 junction circuit from the upper winding of relay 1003 and from the resistance element. and to transfer them to the pulse contacts of the calling device 1001 of position 1, thereby a low resistance bridge is placed across the wires of the junction circuit OT1 to allow control by the calling device of the remotely controlled office switching devices. In addition, the wires of the equipment 1000 are connected to the conversation circuit comprising the left part of the translator coil 1002, the engagement contacts of the calling device 1001 are connected to the conversation wires.

   The operator equipment therefore allows her to speak and transmit on the OT1 junction circuit.



   The attendant can therefore converse with the calling subscriber 500, the connection being established through the control junction circuit via the windings of the translating coil 947, the wires 951 and 952 of the cable and the relay contacts. 703 to the conversation wires 621 and 622 of the connection circuit.



   , when the impulse contacts of the calling device 1001 of office A are connected to the terminals of the wires of the junction circuit OT1, the relay 913 of the common equipment CE1 draws in the junction circuit but the differential relay 912 does not draw not. Relay 915 closes the circuit of relay 914 which connects the common transmit wire 934 to the resting contact of the spring of the relay 913, which prepares the transmission of im-

  <Desc / Clms Page number 27>

 pulses to the local connector. Relay 914 attracts relay 915 as well, this in turn attracts relay 916. Relays 915 and 916 prepare various circuits which will be described later, relay 916 places an earth on blocking wire 935 to prepare the blocking circuits of certain relays.



   Since it is an extension belonging to a set of 10 grouped extensions that is called, the number consists of tens and unit digits indicative of the desired line and one or two group digits indicative of the called extension in the group.



   When the tens digit of the requested number is sent by means of the disc (not shown) of the calling device 1001, the engagement contacts of this disc bypass the conversation wires of the operator's equipment, they remain closed until the calling device has again reached its normal position. The impulse springs of the calling device are momentarily separated a number of times corresponding to the number to be sent, they thus send the desired number of impulses. ' This maneuver is repeated for each of the following digits.



   In the remotely controlled office, relay 913 momentarily releases each time the circuit is opened at the pulse contacts of the calling device, but relay 914, delayed on release, remains engaged, At each momentary release. relay 913 sends a pulse through contacts of relay 914 to common pulse wire 934. While sending the tens digit each of these pulses passes from wire 934 through the contacts of relay 923 and leads to pulse wire 956 of the ascension electromagnet. The pulses then pass through contacts of relay 703 drawn from the connector, they act

  <Desc / Clms Page number 28>

 then on the ascension electromagnet 716.



   As a result of the operation of the lift solenoid 716 the brushes 700 of the connector are stepped up to. that they are placed in front of the desired level in the contact bank. When the brushes of the connector leave their normal position, the shaft springs which associated with the ground wire 624 interconnect the searcher F1 and the LOC connector) connect an additional earth to the wire 624 to ensure that the connection will be preserved from any outlet by the distributor in fig. 8.



  Shaft springs 719 prepare the circuit for release solenoid 718; shaft springs 720 place a positive on wire 725 to start the generator which is to send inrush current to the desired line.



   In the IEC common equipment of fig. 11, relay 918 is an operation delayed relay; it is permanently connected between the common pulse wire 934 and the negative pole of the battery. In addition, the upper winding of relay 919 is connected in parallel with the winding of relay 918. As a result, these two relays attract when sending the first pulse of the train emitted on wire 934. Relay 918 closes the blocking circuit of the relay 919 through its lower winding so as to keep this relay attracted until the relay 918 releases at the end of the sending of the pulse train. Note that relays 922 and 923 constitute a pair of "count" relays which pull completely at the end of sending the tens digit.

   When relay 919 attracts, at the start of sending the tens digit, it closes the circuit of relay 922 through the contacts of relay 923. Relay 922 attracts and closes its own blocking circuit at its lower contacts connected to the relay. wire 933 spokes to earth

  <Desc / Clms Page number 29>

 through the winding of relay 923. Relay 923 is not attracting at this time because it is shorted by the initial supply circuit of relay 922.

   However when the series relay 918 releases, at the end of sending the tens digit, which allows the relay 919 to release, the initial supply circuit of the relay 922 opens but the relay 922 remains attracted by the effect of its blocking circuit which passes through relay 923, relay 923 attracts, When relay 923 attracts, it disconnects the control contacts of relay 919 from the common point of its own winding and, from that of relay 922 and it prepares their connection to the next pair of "count" relays (925 and 926). Relay 923 also disconnects common pulse wire 934 from riser wire 956 and transfers it to spin wire 957 through the contacts of relay 924.

   In order to. keep relay 908 attracted, relay 923 transfers the wire associated with this relay from rotation wire 957 qu ascent wire 956 because the ascent wire 956 has already been used for sending pulses and rotation wire 957 will receive the following pulses, which will probably cause it to be released. tion of relay 908 when it is short-circuited, Since no more pulses will be sent on vertical wire 956 during this call, relay 908 can remain connected to wire 956 until the call is established, this wire remains under the control of relay 703.



   When the units digit is output, on each momentary release of relay 913, a circuit closes through wire 934 and the contacts of relay 903 to terminate in rotation wire 957 through the contacts of relay 924 of the relay. ones digit. These pulses are returned through wire 957 and from the connection relay contacts 703 to the rotation electromagnet 717. The rotation electromagnet

  <Desc / Clms Page number 30>

 717 rotates the brushes 700 of the connector until they reach the pins of the called line, in this case pins 450 of fig. 4 or multiples thereof because the called line is the TPL line to 10 grouped stations.



   The relays 918 and 919 attract again during the sending of the impulses. In order to test the called line to determine if it is busy or free, relay 919 disconnects test lead 960 from the lower winding of relay 921 and connects it to the lower winding of busy test relay 917. . As a result, relay 917 attracts whenever the test brush (brush C) of the brush group 700 of the LOC connector passes over a grounded test contact. In the event that the called line is busy, relay 917 is pulled when the brushes engage pins 450 since terminal C of this group is grounded. Under these conditions, the relay 921 cannot attract and the connection cannot be established as will be shown in detail below.



   If we assume that the called line is free when we call, the relay 917 is not attracted when the brushes 700 of the connector engage on the pins 450. In these conditions the relay 921 attracts in the circuit which passes to through the lower coil of relay 921, wire 935, contacts of relays 919 and 921 to terminate in wire 960. This circuit is extended through contacts of relay 703, contacts of relay 704, brush 700C and 450C brush to the negative of the battery supplying the office by borrowing the cut-off relay circuit (not shown) from the LC2 line circuit.

   The cut-off relay of the called line draws into this circuit in series with the relay 921, it makes it possible to ring the called line and establish the conversation circuit.

  <Desc / Clms Page number 31>

 



   In the IEC equipment, relay 921 closes its blocking circuit through its upper winding to wire 935, at its inner lower contact it transfers wire 960 from the test circuit to wire 955, which ensures the maintenance of an earth on wire 960 during the sending of the group station selection pulse train and provides a more direct earth than that which existed previously and which was given through the lower winding of relay 921. At its upper armature the relay 921 disconnects wire 954 and connects wire 955 for a reason which will be explained later, The coil of relay 924 is powered in parallel with the upper bearing of relay 921 to transfer wire 934 from wire 957 to wire 958 .



   It is necessary to describe code selection more fully so that the special features can be better appreciated in the course of this discussion.



  In a system which makes it possible to connect 10 stations on the same line, the usual arrangement is to provide a grouped station selector such as the PSI selector of FIG. 8; By issuing a single selection digit, the code selector can take one of the 10 desired positions.



  It should be noted that the grouped set PSI selector has 10 work positions which correspond to the 10 groups of contacts shown. The last four contact groups in brush bank 741 and 742 are used to group four fully selectable stations, leaving only six groups available for the 10 station selection code. This difficulty was overcome by using contact groups 2 to 6 of the 741 brush which are used to send the reporting codes of the first five stations grouped on the line, the contact groups 2 to 6 of the 742 brush bank being used to sending the code

  <Desc / Clms Page number 32>

 ringing to the five remaining extensions.

   When it comes to sending the inrush current to any of the first five stations, one of the numbers 2 to 6 is used to select the desired wire from the group of wires 746 terminating at the generator, but when it comes to sending the ringing current to one of the five remaining stations, it is necessary to cause a commutation to substitute brush 742 for brush 741. This is done by sending the number 1 as the number preliminary selection of any one of the last five sets on the line,

   following which one of the selection digits between 1 and G is emitted to advance the selector brushes and to bring the contacts of the brush 741 into contact with any one of the groups from / 2 to 6 and thereby put in circuit any of the wires 742 of the code generator,
To show all the advantages of the recommended operating mode, it will be assumed that one wishes to call the tenth group set on the line, the part of the number of this set intended to make the selection in the group is made up of the digits 1 and 5, it follows the tens and units digits that perform the selection of the row itself.



  If so, the attendant transmits the digits 1 and 5 after transmitting the tens and units digits.



     Returning to the detailed description of the operation, it can be seen that when the attendant sends the digit 1 / selection in the group, after having sent the units digit, a pulse is sent by relay 913 on the wire. common pulse 934. This pulse is transmitted through the contacts of relays 923, 924, 926 and 928 to the control wire 958 of the group station selector. This pulse passes through the contacts of relay 703 and ends at the control solenoid 743 of selector PS1. When

  <Desc / Clms Page number 33>

 the electromagnet 743 operates, the brushes 741 and 742 advance by one step to prepare the circuit which will receive the next number for selecting grouped stations.



   When brush 742 stops on the first group of contacts and therefore jumps them, a series circuit is prepared for relay 713 and relay 920 (of the common equipment CE1) through pilot wire 959, but this circuit remains open until relay 918 releases at the end of sending the digit in order to prevent relays 713 and 920 attracting when a higher value digit is sent as the first digit of selection of the group set.



   When relay 918 releases, relays 713 and 920 attract. Relay 920 immediately attracts into this circuit but the attraction of relay 713 is somewhat delayed due to its special characteristic. When relay 920 attracts, it closes its blocking circuit at its lower inner contacts connected to wire 935, it bypasses the upper contacts of relay 926 to prevent the latter from opening the impulse circuit passing through the wire.958 and leading to the group selector control electromagnet as it would if it were not so.



   The relays 923 and 924 of the tens and units digits being attracted, the attraction of the relay 919, comas 11 has been said above, has for result to make attract and block the relay 929 at the beginning of the sending of the first one. group station selection digit, and releasing relay 919 at the end of sending this digit causes relay 926 to be drawn into the blocking circuit of relay 925.



   In the LOC connector, relay 713 attracts to attract relay 920, it closes its blocking circuit to wire 734 Relay 713 also transfers the wire of generator 754 from contacts 2 to 6 of brush 741 to contacts 2 to 6 of brush 742 which prepares the sending of the inrush current to one of the stations of the second group of five connected on the line

  <Desc / Clms Page number 34>

 called instead of sending it to one of the extensions in the first group of five.



   When the second group station select digit (assumed to be digit 5) is transmitted, the five pulses are transmitted by relay 913 on wire 958. ' These pulses pass through the contacts of the relays 923, 924 and 923 and through the contacts of the idle relay 928. The electronic control 743 therefore receives five additional pulses.



  It advances the brushes 741 and 742 from the first position to the sixth.



   When relay 919 attracts at the start of sending the second digit for selecting the group stations, it closes the circuit of relay 927 through contacts of attracted relays 923, 924 and 926 and through contacts of relay 928. The relay 927 pulls in and closes its own blocking circuit in series with relay 928. As a result, relay 928 pulls in series with relay 927 when the initial power supply circuit of relay 927 is opened when relay 919 releases. the end of transmission of the second digit for selecting the group set.



   The relay 928 finally opens the supply circuit of the metering relay to its upper inner contacts and to its upper contacts it opens the supply circuit which borrows the wire 958.



   When the operator of office A has sent the requested number, she brings the key K1 in fig. 12 in the normal position which allows relay 1006 to release and disengage equipment 1000 and 1001 from the junction circuit OT1. Relay 1006 again places the upper winding of line relay 1003 at the terminals of the upper wires of the relay circuit. junction, this relay draws back into the junction circuit in series with the line relay of the remote office and

  <Desc / Clms Page number 35>

 disconnects signaling relay 1004 before relay 1005 can release and pull relay. 1004 through the contacts of relay 1003.

   The release of relay 1005 is momentarily delayed because current flows through the relay winding and through the shunt resistor to give relay 1003 time to disconnect relay 1004,
In the remote controlled office, the relay 913 of the CE1 unit of the common equipment returns to idle and remains released when the relay 1001 is released, because the current flowing through the upper winding of the relay 1003 and the resistance associated with it is insufficient to keep relay 913 attracted,
Relay 913 sends a pulse, on common pulse wire 934, to relays 918 and 919 but this pulse has no effect on the local connector because the pulse circuit is open at the upper contacts of relay 928 .



   The relays 914, 915 and 916 now release at short successive intervals, each of them remaining delayed on release. Relay 914 cuts off the pulse sent on wire 934 and allows relays 918 and 919 to release.



  Positive is held on blocking wire 905 until relay 916 releases. When relay 915 releases, the circuit of relay 712 closes through contacts of relay 915 and relay 916 while still attracted, unattracted contacts of relay 917, drawn contacts of relay 955 and contacts of relay 703.



   Relay 702 pulls and locks in multiple with the coil of relay 701 through the top inner contacts of relay 701 to grounded guard wire 623.



  The connection relay 703 is disconnected by the normally closed contacts controlled by the lower springs

  <Desc / Clms Page number 36>

 interiors of relay 703, it therefore releases and separates the local connector of unit CE1 from the common equipment.



   In the IEC common equipment relay: '08 which has been kept attracted, through wire 936, since relay 923 has drawn at the end of the tens digit, releases when relay 703 is released. relay 908 opens the blocking circuits of relays 907 and 909 and allows them to be released,
The slow-to-run relay 916 releases soon after and removes the earth from wire 955 allowing the relays that have been jammed in fig.

   11 to release, With relays 916 and 908 released, a positive is removed from wire 930 to allow relay 901 to release unless a new call has arrived in the meantime and subsequent operations have been carried out until 'At the time relay 805 has pulled in, in this case common equipment CE2 has been selected and relay 805 keeps wire 930 grounded so that relay 901 remains pulled through its lower inner contacts until that the distributor D has completed its operating cycle.



   In all cases, relay 901 releases when wire 930 is finally no longer connected to earth. When this occurs it again prepares for transmission of the next "tap" pulse through wire 952 associated with equipment CE2 instead of wire 961 associated with common equipment CE1.



   When relay 702 pulls, as described above, it connects wire 735 to relay 711 through occupancy relay contacts 704 and shaft springs 724 of the "O" level. At the same time, relay 702 places a ground on wire 756 through the contacts of relays 70 and 710 in order to start the switch.

  <Desc / Clms Page number 37>

 ringtone and the code generator device. The generator of the inrush current itself having started by the action of the starter wire 727 when the shaft springs 720 have been activated.



   As soon as wire 735 has been grounded, relay 711 which serves as a socket and switching relay (brush connection relay) draws into the circuit which includes wire 735, it closes its own starting circuit. to wire 734 and at the same time opens the circuit of wire 735. Relay 711 connects the negative and positive brushes of group 700 and prepares the circuit for sending the inrush current and the conversion circuit, it also establishes the calling circuit to its upper inner contacts, through contacts of the drawn relay 713 and the contacts of the brush 742 in the sixth position.

   It follows that an inrush current according to a determined code is received on the wire 747 of the code generator, this code consists of a long stroke followed by five short strokes, this inrush current passes through the contacts of the sixth position of brush 742, the contacts of the drawn relays 713 and 711, the upper coil of the relay 710, the contacts of the biased relay 714, the contacts of the relay 715, the upper contacts of the relays 710 and 711, the negative brush 700 and group 450 of the corresponding terminals to lead to the negative wire of the TPL line with 10 grouped stations.

   The inrush current passes through the bell of extension 400 and in each of the nine other bells connected to the line, (assuming the TPL line is fully equipped), it returns to earth through the positive wire of the line. and the positive terminal of group 450, the positive brush '700, the contacts of the relays 711 and 710, the upper contacts of the relay 715.



  The inrush current is superimposed on the negative polarity of the battery powering the desktop, as is normal.

  <Desc / Clms Page number 38>

 



   When the called subscriber of extension 400 answers, closing the direct current bridge placed on the wires of his line allows relay 710 to attract. At its lower internal contact, relay 710 closes its own blocking circuit through its lower winding by borrowing wire 734.



  Relay 710 also opens the inrush current sending circuit and closes the talk circuit to its upper inner contacts. Additionally, relay 710 removes the positive from wire 736 to prevent unnecessary operation of the silk current switch.



   The impedance 709 supplies the current necessary for the conversation to the called station through the contacts of the operated selection relay 701.



   Calling and called subscribers can now talk to each other as they wish.



   While the inrush current is sent to the called line, the calling subscriber receives information that the communication has been established correctly in that he receives an echo of the sending of ringing current through the low capacity capacitors 731 and 732 interposed between the calling circuit and the incoming conversation wires 621 and 622. When the conversation is over and the subscribers have hung up their receiver, the circuit of relay 701 of the connector is interrupted local has the effect of releasing relays 706 and 707. With relay 702 attracted and blocked to wire 623, releasing relay 707 has the effect of removing the positive from blocking wire 723.

   This opens the blocking circuit of relay 702 which releases and again applies ground to wire 623, but the connection of a ground to this wire is delayed somewhat due to the characteristics of relay 702 which is delayed on release. The 701 relays,

  <Desc / Clms Page number 39>

 710, 711 and, 713 release when the connector returns to rest. In addition, and during this interval, a positive is removed from the ground wire 623. The finder relay 601 releases as does the relay 302 of the LC1 line circuit.



   The LC2 line circuit cut-off relay releases and the guard polarity is removed from wire C of the called line when the brush 700C of the local LOC connector is no longer connected to earth when the relay is released. 702.



   The local connector is returned to the normal position when the releasing solenoid 718 draws through the shaft springs 719 when the relay 701 releases. The release solenoid circuit is opened at shaft springs 719 when the connector returns to the home position. The selector PS1 of the grouped stations is released by the operation of the release solenoid 744 through the shaft springs 745.



   In the researcher Fl, the brushes 600 are disconnected when the relay 601 releases. In addition, the circuit of the release solenoid 605, closes through the contacts of relay 601, the shaft springs 606 and contacts of relay 602. The solenoid 605 attracts this. made to bring the finder Fl in the normal position. Thereby the circuit of the release solenoid is opened to the shaft springs 606.



   When the local LOC connector has returned to its normal position, the positive is removed at a point on the ground wire 624 by the connector shaft springs and furthermore the earth is permanently removed from the ground wire 624 when the springs of shaft 607 of the researcher Fl have returned to the rest position, as shown on the plan, The earth is therefore removed from the test wire 851.



  In order to explain the operations that are carried out

  <Desc / Clms Page number 40>

 when a line is called while it is already in conversation, it will be assumed that the TPL line with 10 grouped stations in fig. 4 is busy when the subscriber of extension 300 of the EPL line makes a call to the subscriber of extension 400 connected to the TPL line, as has been said above. In this case, the operations are carried out as described previously until the ones digit is transmitted by the operator and the pulses of this digit, received by the rotation electromagnet 717 of the local connector, cause the brushes 700 to rotate which engage on the terminals 450 associated with the busy line TPL.

   At this moment, the earth, connected to pin 0 of group 450 and the multiples thereof, is encountered by the brush 7000 of the local connector: it is therefore extended through the contacts of the occupancy relay 704, contacts of relay 703 and test lead 760 to common equipment CE1; From test lead 960, this earth extends through the contacts of relay 961 to the lower inner contacts of rolais 919. It will be remembered that relays 918 and 919 are kept attracted while sending the pulses. As a result, the earth encountered is extended through the lower inner contacts of relay 919 to the lower winding of relay 917.

   The relay 917 therefore attracts to prepare its own blocking circuit for its lower armature; this circuit borrows wire 935 and the normally closed contacts controlled by the inner lower spring of r @ lais 919 when the latter releases at the end of sending the units digit. Relay 917 also prepares a special circuit for blocking using its upper winding; it prepares the transmission of a pulse on wire 935, it prepares the transmission of a pulse on wire 953;

   on its upper contact, it establishes a connection of the common wire 936 of the

  <Desc / Clms Page number 41>

 busy tone through the capacitor limiting the current to the lower wire of the junction circuit which allows the attendant to hear the busy tone which is induced through the windings of the coil 947, so that it can also be heard by the calling subscriber. In addition, the lower winding of relay 924 is fed in multiple with the lower winding 917 through the lower contacts of relay 919 to disconnect wire 957 and prevent further advance of brushes 700 when the operator releases the switch. common equipment unit.

   At its lower contacts, relay 924 locks itself to the winding of relay 917 by bypassing the lower contacts of relay 919.



   When the attendant puts her key back in the rest position, as mentioned above to release the common equipment, release relays 913 to 916 and unlock and release the other relays on the unit Common equipment IEC is performed in principle as described above. When relay 913 releases, it closes the blocking circuit which has been prepared through the top winding of relay 917, contacts relay 916 to keep relay 917 attracted regardless of the existence of a ground on the wire. line test, after relay 919 has responded to the action of a given pulse when releasing relay 913.

   When relay 914 is released, a pulse is sent through contacts of relay 917 and through wire 953 to relay 704 of the local connector. Relay 704 attracts and closes its own blocking circuit to wire 623.



   A moment later, i.e. after sufficient time has been allocated to relay 704 to attract and close its blocking circuit, relay 915 releases and opens the

  <Desc / Clms Page number 42>

 initial circuit for supplying relay 704 to its upper contact, at its upper internal contact it closes the circuit of relay 702 through contacts of relay 916. This circuit borrows wire 955 as described above except that it now includes the closed contact of relay 917 instead of the closed contact of relay 921. Relay 702 attracts and as described above releases relay 703 which releases the common equipment unit CE1 from the local connector.



  A moment later, relay 916 releases. This last operation, as well as the release of the rest of the relays of the IEC unit, completes the disabling of the unit as described above. In the local connector LOC, the relay 702 being attracted, the maintenance of a ground on the wire 623 is placed under the control of the contacts of the relay 707; wires 735 and 736 remain disconnected at the contacts of relay 704.



  The busy tone wire 726 is disconnected at the upper talk wire 621 at the upper contacts of the busy relay 704 through the current limiting capacitor 727, and a circuit back to ground is given. through lower talk wire 622, contacts of relay 704 and the capacitor. It should be noted that the earth cannot be applied through the brush 700C to the wire C of the line called by the attraction of the relay 702, because the circuit which ends at the brush 700C is interrupted by the contacts normally closed relay 704.



   When the calling subscriber is informed that his correspondent is busy, by sending the busy tone as indicated previously, he hangs up his receiver, relay 706 releases and releases the relay. 707 such that the connecting circuit and the calling line circuit are released as described above.

  <Desc / Clms Page number 43>

 



   The system which is set forth here is designed so that any subscriber can be served by each of the lines of a group of two or more multiple lines. Although it is more common for multiple line service to be given through individual lines or at least through lines to which a very small number of stations are connected, the circuit arrangements are such that It is possible to give the service of multiple lines to lines with grouped sets and any of these regardless of the call code used in the event that another line is available for connection to the station of the group. 'subscriber.



  The most complicated case which can arise for the circuit of the common equipment units relates to the service with multiple lines when the assigned code is a two-digit code necessary for the selection of the station in the group; this is the case which is described below. For this purpose, it is assumed that the subscriber of set 400 in the group has multiple line service and that a second line goes from the central office to his set and that one set is connected to this line. It is necessary that the same code be used to ring, on each of the lines, the subscriber having the service by multiple lines. In addition, it is essential that both lines can be reached at the same level of connectors and it is further preferable that they can be connected to neighboring pins in the connector bank.

   Assume that the second line of the subscriber is connected to the group of pins following the connector immediately in the bank / group of pins 450 to which the TPL line is connected. For the purposes of the description, it will be assumed that the subscriber of set 300 makes a call and that he asks the operator to be connected to set 400; when the operator has called this number and the TPL line is found busy, when the brushes 700 of the LOC connector arrive on it,

  <Desc / Clms Page number 44>

 the test being carried out before the transmission of the part of the number making the selection of the set in the group.

   It will be remembered that this results from the fact that the relay 917 has drawn through contacts of the relay 919 at the end of the sending of the second digit and due to the closing of the local blocking circuit passing through the lower winding of the relay 917 when the relay 919 releases at the end of the transmission of the second digit or digits of the units.



  It will also be recalled that the busy tone is applied to the upper contacts of relay 917 on the conversation wires so that this tone can be heard by the calling subscriber and by the operator. When the called subscriber has multiple line service, the attendant does not immediately return the key to the normal position to allow the connection to be released, as described previously. Rather, it transmits the part of the call number which relates to the selection in the group although it hears the busy tone.



  It then emits an additional number 1 to cause the connector brushes to advance to the next line. Remember that the lower winding of relay 924 is fed in multiple with the lower winding of relay 917 when relay 919 releases and it connects wire 934 to wire 958, which causes the transmission of the first digit of selection 1 towards the control electro 743 of the PSI selector, and the advancement of the brushes 741 and 742. The relay 924 remains attracted, in parallel with the lower winding of the relay 917, through its lower contacts.



   The circuit of the lower winding of the relay 924 is opened as a result of the attraction of the relay 926 at the end of the sending of the first selection pulse in the group but the relay remains attracted since in this case the first digit selection in the group is the number 1 and that, consequently, the relay 920 has attracted to bypass the contacts of the

  <Desc / Clms Page number 45>

 relay 926. The lower winding of relay 924 is opened as a result of the pulling of relay 928 at the end of sending the second select digit in the group, so that relay 924 releases and transfers the signal again. control wire 934 to wire 957.



   As a result, when the attendant issues a new special number 1, the pulse she sends is transmitted from the common pulse wire 934 through wire 957 to the rotation electromagnet 717 of the local connector. LOO.



  This causes the brushes 7000 to advance by one step, which engage on the spindle at which the following line ends.



  The following operations now depend on whether the line is busy or free. If this line is busy, relay 917 of the common equipment unit remains engaged and the busy tone continues to be sent on the line. In the event that the called subscriber has a third line, the attendant can once again emit the special number 1 to cause the connector brushes to advance on the third line being tested. These maneuvers can continue until the test of all the bench contacts of this level has been carried out if necessary.



   For the sake of the description, it will now be assumed that the next line is free instead of being occupied as mentioned above. Under these conditions, when relay 919 attracts again when sending the special digit 1 and disconnects the lower winding of relay 917 from the local blocking circuit and reconnects this winding to brush 7000, the relay 917 releases which opens the local blocking circuit at another point. When relay 919 releases, the lower winding of relay 921 is energized through test lead 960 and through brush 7000 in series with the called-line cutoff relay.

   Relay

  <Desc / Clms Page number 46>

 921 closes its blocking circuit to wire 935 and through its upper winding, it prepares the emission of a pulse on wire 955 and it bypasses its lower winding and the contacts of relay 919 by connecting wire 935 which is grounded to wire 960, which prevents the connection being cut when relay 919 operates again.



   At this point, the operation is identical to that described above, the common equipment CE1 is released when the operator replaces the answer key K1. in the idle position, the local connector LOC sends the inrush current to the called station on the called line and completes the conversation circuit when the called subscriber answers.



   For the purpose of explaining how calls are made to the four-station bundle lines, such as the FPL line of fig. 3, and how the called set is rung to the exclusion of the three other grouped sets on the line, it will be assumed that the subscriber of set 400 of the TPL line, with 10 grouped sets, wishes to get in touch with the group. subscriber to set 300 of the FPL grouped four-set line, it should be understood that when the four-set TPL line is fully equipped, two of the rings are connected between a wire and the earth and that the other two rings are connected between the other wire and the earth, the two rings connected between each of the conductors and the earth are biased in the opposite direction.

   It should further be understood that the usual arrangement - it is used at the stations, i.e. there is a relay at each station bridged on the line wires in series with a capacitor so that it attracts when sends the alternating current to connect the bell associated with it between the earth and the wire of the line which has been chosen, so that there is normally no direct current passing through

  <Desc / Clms Page number 47>

 ringtones. Preferably, high resistance rings are used or a relatively high resistance is connected in series with them to limit the value of the direct current during the inrush current return period and to make it possible to obtain a current. louder to attract the call cut relay when the called subscriber answers.



   It will be assumed that when the subscriber of set 400 picks up his receiver, the researcher Fl is the one which has been preselected by the distributor D and that the common equipment CE1 is free and that it is consequently put into service by the local connector LOC when the researcher Fl searches for the line circuit LC2 of FIG. 4 in a manner identical to that which has been described above.



   When the attendant answers and the requested number is communicated to her, she emits the digits of this number, which first causes one of the brushes 700 of the LOC local connector to be brought in front of the desired level and then the rotation. of these brushes until they engage on pins 350 or multiples thereof, the attendant then sends the last digit which is the selection digit of the set in the group and then releases her equipment to allow the CE1 equipment unit to return to the rest position.



   If it is assumed that the subscriber of extension 300 is the first in the group of the line with four grouped extensions, the selection number in the group assigned to this extension will be number 7.



  Therefore, the brushes 741 and 742 are brought to the 'seventh. group of contacts by the operation of the electro 742 following the sending of the digit for selecting the station in the group. The contacts of the seventh position of the brush 741 are not connected, but the brush 743 in this position

  <Desc / Clms Page number 48>

 bridges the contacts which closes the circuit of relay 714. This relay being attracted, the upper terminal of the upper winding of relay 710 is disconnected from negative brush 700 and is transferred to wire 733 which is the positive of the generator.

   In addition, a connection is made from the lower terminal of the upper coil of relay 710 to negative brush 700 to the contacts of relay 714 which prepares the transmission of ringing current on the negative wire of the called line through. the upper winding of the relay 710. It follows, if it is assumed that the called line is free when the unit of the common equipment is released that the relay 711 attracts for a certain time to establish the circuit for sending the current call.

   Each time the inrush current interrupter (not shown) applies a positive superimposed to the inrush current on wire 733, that current flows through one of the contacts of relay 714, the top winding of relay 710. , contacts of relay 711, additional contacts of relay 714, contacts of relay 715, upper contacts of relay 710 and contacts of relay 711 to terminate at the negative wire of the FPL line through the negative brush 700.



  The biased bell at station 300 is therefore fed between the negative wire of the line and the earth.



   The current which circulates in the upper winding of the relay 710 during the call is insufficient to cause the attraction of the relay because the latter is specially adjusted so as not to attract under a current of the considered value.



   When the subscriber of set 300 picks up his receiver and closes the DC bridge and low resistance at the terminals of the FPL line, the current flows in the circuit for sending the inrush current which has been described below. above and in a circuit which borrows the positive wire of the line to lead

  <Desc / Clms Page number 49>

 positive at the upper contacts of relay 715, this current is sufficient to attract relay 710 under the action of its upper winding. The relay 710 closes its blocking circuit through its lower winding, it opens the circuit for sending the ringing current and it completes the conversation circuit.



  The conversation can therefore be established.



   The connection which has been established is released as described above when the calling subscriber hangs up his receiver.



   When the LOO connector is put into service to establish a communication to the second station of the group formed on a line such as the LP line in fig. 3, the selection digit, in the group to be output is digit 8.



  In this case, the brush 742 bridges the contacts of the eighth position and therefore closes the circuit of the relay 712. Therefore, when the relay 711 attracts, the ringing current is transmitted from the negative wire 754 of the generator through one of the contacts of the generator. relay 711, the upper winding of relay 710, from the contacts of relays 714, 715, 710 and 711 to the negative wire of the line called up via the negative brush 700. Note that the winding upper relay 710 is incorporated in the circuit for sending the inrush current in the opposite direction to that existing when relay 714 was pulled.

   This reversal is made in the event that the inrush current of the positive wire 753 of the generator is applied in order to maintain the magnetization polarity of the upper winding of the relay 710 continuously in the same direction so that when this winding is energized, it closes the relay blocking circuit through the lower winding if the polarities of the two windings have an additive effect.



   It should be noted that when the third station in the group

  <Desc / Clms Page number 50>

 placed on the line is called, the relay 714: attracts through the contacts of the ninth position of the brush 742 as happened when the brush was in the seventh position and the relay 712 attracts through the contacts of the tenth position of broom 742, when the fourth station in the line is to be called, as happened in the eighth position of broom 742 when it was the second station to be called.

   In order to distinguish the seventh and eighth positions of the PSI selector on the one hand and the ninth and tenth positions of this selector on the other hand, the relay 715 is connected to the contacts of the ninth and tenth positions of the brush 741, from such that it attracts when the group station selection digit emitted either 9 or 10, to reverse the connection between the calling circuit and the line wires. The relay 715 being attracted, it should be noted that the inrush current transmitted borrows the positive brush 700 and that the return circuit towards the earth borrows the negative brush 700.

   In this way, the third and fourth grouped extensions on the line are ringed exactly the same as the first and second, except that inrush current is applied to the other talk wire as a result of the call. attraction of relay 715.



   Arrangements have been made to automatically block lines which become defective. To describe this characteristic, it will be assumed that the line of the station 300 becomes defective, so that the relay 301 attracts as a result of the fault, but not because a call is made. It can be assumed that the researcher F1 of FIG. l is the one which answers the call and that the common equipment CE1 is the one which is put into service. When the attendant answers, she cannot find a correspondent at the end of the line, so she frees the connection without sending a pulse.

   In that case,

  <Desc / Clms Page number 51>

 neither relay 917 nor relay 921 .. 'attracts. Therefore, when relay 915 releases, it closes the circuit of relay 708 through contacts of relay 916, contacts of relays 917 and 921, wire 954 and contacts of relay 703. Relay 708 attracts and removes the earth of the wire 623, ae which unlocks and returns to rest all the relays which are drawn into the connection circuit. The connector is released when the relay 701 releases and the finder Fl is released when the relay 601 is released and the circuit of the release solenoid 605 is closed.



   In the LC1 circuit associated with the FPL line, which we assume to be defective, the relay 302 releases following the release of the relay 601, of the researcher Fl and opens the blocking circuit of the relay 303 in addition to resetting the relay. 301 on. Since the line is faulty, relay 301 immediately draws when reconnected by relay 302, it closes the blocking circuit of the drawn relay 303 at its lower contacts. Relay 303 remains engaged in the blocking circuit which includes the lower contact of relay 301 until the faulty line has returned to normal condition, at which point relay 303 releases following the release. of relay 301.



   Note that when relay 303 is pulled, it keeps starter wire 361 disconnected at its bottom armature and keeps relay 302 disconnected from pin 351C so as to prevent seizure of the line by a searcher who searches for another line, because the upper contacts of relay 301 are closed.

   It will be noted that this arrangement is especially advantageous in the case of an office controlled remotely and not supervised because the faulty line faulting prevents untimely occupation.

  <Desc / Clms Page number 52>

 connection circuits, if this occupation could take place it could subsequently affect the service even if it is admitted that only a small number of the lines can become defective since only seven connection circuits out of ten are ordinarily provided in an office of 100 lines.



   In the event that a subscriber inadvertently calls an unassigned number and the digits sent by the operator cause the brush to advance of a connector such as the LOC connector in fig. 7 and 8 on a group of free bank contacts, none of the test relays 917 and 921 will be able to draw, because no connection is made through wire 960 and brush 700C through wire C of the group of unassigned pins. In this case, when the attendant releases the common equipment after sending the number, wire 954 is momentarily grounded instead of wire 955. As a result, local connector relay 708 attracts instead of relay 702.



  When the relay 708 attracts it causes the release of the connection circuit as described above.



   In addition, the calling line is faulted in the manner described. It remains in this state until the calling subscriber has hung up his receiver and allowed the line circuit to return to normal condition.



   With the arrangement just described, a trunk circuit becomes immediately available for common use again when it has been inadvertently brought into service to establish a connection to a group of unassigned bank contacts. This arrangement therefore gives a more efficient use of the connection circuits than any other system.



   How unanswered calls are handled will be described below. For this purpose, it will be assumed that a call is made by a subscriber as described above.

  <Desc / Clms Page number 53>

 previously, that the connection circuit of fig. 6, 7 and 8 and the CE common equipment have been put into service and which the operator of office A neglects to respond within a reasonable time. This failure can be caused for example by a fault occurring on the control junction circuit or when a fault occurs in the equipment at office A.



  Under these conditions, the time response device of which it was previously questioned and composed of the relays 909 and 911 operates under the control of the time device T as will be explained below.



   Recall that relay 908 attracts when the IEC unit of the common equipment is first put into service and connects a ground to wire 931 through the contacts of relay 909, and connects also wire 932 through the contacts of relay 909 to the winding of relay 911. The time T device which may be of any known construction is turned on when a positive is connected to wire 931. It turns on the time switch. wire 932 temporarily to the ground to make the relay 911 attract. When the relay 911 attracts it locks to the positive taken through the contacts of the relay 909 and it opens its initial circuit of supply.



   Relay 911 also prepares the circuit for the top winding of relay 910 through wire 933.



  After a certain time, long enough to allow the operator in office A to answer the call in the normal way and in the event that the 909 relay did not draw to release the 911 relay, as the attendant does when she answers, a positive placed on wire 933 by the timing device feeds the upper winding of relay 910 through contacts of relay 911. Relay 910 is blocked by the intermediary. from its lower earth contacts taken through the contacts of relay 909; to his lower contacts he plaoe

  <Desc / Clms Page number 54>

 an earth on wire 949.



   It is assumed that this wire goes to an alarm device which may be mounted outside the building in which the equipment is located, or which may be located a short distance into the dwelling of some local personality to whom we entrust the task of responding in urgent cases. Positive is held on wire 949 and relays 910 and 911 remain stuck until the call is answered and relay 909 attracts.



   A wire identical to alarm wire 949 is provided in the common equipment CE2, these two wires are normally connected together and extend to the same alarm device; in this way, a tear is given when the operator does not respond regardless of the common equipment that has been put into service.



   A local LCS control station shown in fig. 10 and 20 is provided and connected to the two common equipment units CE1 and CE2.



   It can now be assumed that a call on either one of the common equipment units CE1 and CE2 went unanswered for a time long enough for the no answer alarm to function as said above. . In this case, the person in charge of the local control of the office can carry out the control by means of the device which is in the building of the central office and can establish the calls either partially or completely.



   It can be seen that the LCS local control group in principle comprises a standard automatic telephone but that it does not have fork contacts 1709, a micro-telephone T., a receiver R and a dial-type calling device 1710 associated with the negative and positive conversation wires 1705 and 1706. The local control device further comprises a

  <Desc / Clms Page number 55>

 buzzer 1708 connected between the negative pole of the battery supplying the office and the signal wires 1707 as well as the control keys CK1 and CK2 connected to wires 1701 to 1704.



   It can be assumed in the first place that the local operator of office B when informed that a no response alarm has been sent wishes to temporarily relinquish control of the remote office on the assumption that the existing fault can be quickly resolved. . In this case, - the local operator moves the key CK1 in the desired direction.

   Assuming that the unanswered call is blocked in the IEC common equipment unit and that it is from this common equipment unit that the alarm signal was given by the intermediary alarm wire 949, when the partial control key CK1 is moved to the left the left key aette contacts apply an earth to the transfer wires 1702 which extends an earth via the wire 947 up to the Coilover of Relay 905. Relay 905 draws and transfers the talk circuits associated with common equipment CE1, through the terminals shown, to talk wires 1705 and 1706 of the LOS local control group.

   Relay 905 at its lower contacts now closes the circuit to buzzer 1708 through wire 946 and wire 1707.



  This circuit comprises contacts of relay 908 of the common equipment unit and contacts of relay 916. As a result of the closing of this circuit, buzzer 1708 of the local control device is activated, indicating to the operator that the common IEC equipment is blocked by a call that has not been answered. In order to answer the call, the local operator picks up her receiver R which closes the fork contacts 1709, the receiver R and the microphone T being connected in line in series with the pulse contacts of the device

  <Desc / Clms Page number 56>

 call 1710 to the terminals of the negative and positive conversation wires 1705 and 1706.

   By this action, the circuit of relay 913 closes through the contacts of relay 905 and the windings of the translating coil 947. Relay 913 attracts and performs the same operations as those which have been described in connection with the response of the relay. operator at office A. Buzzer 1708 stops working when its circuit is open to the lower contacts of relay 916. In addition, relay 909 draws through the contacts of relay 904 to disconnect the device in time T and to unblock and release relays 910 and 911, allowing the no answer alarm to cease unless there is another unanswered call that is on hold in common equipment THESE.



   The local control operator can get in touch with the calling subscriber and inquire about the desired number. It can send the requested number using the 171Q calling device.



  When she has finished sending the desired number, this attendant can hang up her receiver, which cuts contacts 1709 and allows relay 913 to release and CE1 of common equipment to release.



   In the event that the local control operator wishes to be released from partial control of the CE2 unit of the common equipment, she actuates the control key CK1 to the right which causes the connection of an earth on the wire. transfer 1704. This draws the relay of the common equipment CE2 corresponding to the relay 905 of the common equipment unit CE1, this gives results identical to those which have been described previously.

   It should be noted that in the event that one of the junction circuits becomes defective, the local control operator can leave the control key CK1 lowered in the corresponding direction, she can thus respond locally and reserve locally. establishment of all

  <Desc / Clms Page number 57>

 calls received on the corresponding common equipment unit; calls that are received on the other unit of common equipment pass through the remaining trunk circuit and reach the control switch, office A. It will now be assumed that the local operator wishes to take full control of the establishment communications in the office B.

   It can do this by associating the LCS local control group with either of the two common control units; at the same time, it deactivates the other unit and thus prevents the sending of calls through the other trunk circuit. In this case, all calls are received by the LCS local control group. It will be assumed that the local control operator wishes to use the CE1 common equipment unit when she takes full control of the establishment of communications (the choice is arbitrary unless one of the two Units or the the equipment associated with it has become defective), in this case, the operator moves the total control key CK2 to the left and thereby places an earth on wire 1702 which is extended through wire 947 to 'to relay 905 of the IEC common equipment.

   Relay 905 attracts and transfers the talk wires of the CE1 unit from the common equipment of the OT1 trunk circuit to the LCS local control group. At the same time, the lower left contacts of the total control CK2 key place a ground on the switch wires 1703 which extends the ground through wire 944 'to terminals 942' and 943 'of the equipment. common CES corresponding to terminals 942 and 943 of the CE1 common equipment. As a result, the relay of the CES unit, corresponding to the IEC relay 901, attracts to indicate to the distributor D of FIG. 9 that the CE2 common equipment cannot be put into service.

   Under these conditions, all the calls are directed to the common equipment CE1 and none of them is

  <Desc / Clms Page number 58>

 transmitted to the CES equipment since the selection wire 962 is kept open at the relay contacts of the common equipment CE2 which correspond to the relay 901. In this way, each call sent is received through the common equipment CE1 to the LCS local control group. It should be noted that the total control key CK2 being operated to the left and the relay 905 being 'attracted, each time the relay 908 attracts, it closes the circuit of the buzzer 1708 through the wires 1746 and 1707 to warn the local operator who can respond by picking up the receiver R which closes the contacts of the fork 1709.

   When the need to control office B locally has disappeared, the local operator returns key CK2 to the normal position; relay 905 releases as well as the relay of common equipment unit CE2 corresponding to relay 901 of CE1. At this time, the calls sent are transmitted on the trunk circuits OT1 and OT2 as described previously.



   The functions performed when all connection circuits to office B are occupied will be described below.



  Wire 861 through the ground equipment is applied to the lower terminal of the relay winding 802 and normally ground to each of the unoccupied connection circuits.



  A positive being connected to wire 861, a contact of the bench of the test brush 821 associated with a group of contacts not used for the extension of the connection towards the researchers such as Fl remains grounded. This connection is open when relay 602 attracts due to the fact that finder Fl has been turned on and the ground connection remains open at contacts 606 after the finder has operated and relay 602 has released until the researcher has returned to rest after being put into service. Removing the earth of a finder from the 861 common thread has no effect

  <Desc / Clms Page number 59>

 as long as the earth remains connected on this wire to one or more other researchers.

   However, when all but one finder is on and ground is held on wire 861 in a single finder and that one is turned on, wire 861 is cut from the direct connection to ground.



   When all of the distributor's relays 821 to 825 are running in search of a free seeker, none of them is found since they are all in service. Brush 821 finds an unconnected ground contact when it encounters the contact to which wire 861 is connected. The brushes of the distributor D stop, the brush 821 being associated with the wire 861. The circuit of the relay 851 is prepared in series with the control electromagnet 800 of the distributor D, but nothing is happening at this moment because that the junction circuit OT1 and the common equipment CE1 are already in service. As soon as the common equipment unit CE1 becomes free and relays 908 and 914 release a ground is placed on the upper terminal of the relay 851 winding.

   This closes the circuit of this relay by means of a branching of the wire 861 which extends through the contacts of the brush bank 821, the brush 821, the contacts of the relay 802, the switch contacts of the electro - magnet 800, the winding of the control electromagnet 800 up to the unconnected pole of the battery supplying the office.



   Relay 861 attracts in this circuit, but electromagnet 800 does not operate due to the relatively high resistance of relay 861. Note that relay 802 cannot attract at this time, even though relay 801 attracts, because it is short-circuited by the connection made to wire 861 through brush 821.



   When relay 851 attracts, it closes its own blocking circuit to its internal, independent upper contacts.

  <Desc / Clms Page number 60>

 of the contacts of relays 908 and 914; he prepares the connection of the busy tone to the conversation circuit at his superior contacts; at its lower contacts it closes the circuit of the lower winding of relay 855 through the contacts of relays 908 and 916. Relay 855 attracts and closes its blocking circuit through the upper winding and the upper contacts of the relay. 854 and the contacts of the drawn relay 851.

   At its two highest contacts, relay 855 establishes the busy tone circuit coming from wire 858 and ending in one of the talk wires, it completes the circuit back to earth through the relay contacts. 853 and capacitor 860, at its lower middle contact, it closes the circuit of relay 906 by earthing the lower internal contacts of relay 852 through the contacts of relay 907. Relay 906 attracts, it opens momentarily. the negative wire of the OT1 junction circuit to warn the operator of office A and it closes the circuit of the relay 907. The relay 907 attracts, after a short moment and closes its own blocking circuit, it opens the relay circuit. signal 106 and releases it.



   In this way, the attendant of office A is called through the OT1 junction circuit, she answers this call as she normally does for the others, that is to say that the relay 913 and the relays 914 to 916 attract. However, the attendant in this case hears the busy signal which is sent through the lower conversation wire (to the right of the translator coil;: '1: 7) and borrows wire 958, the upper conversation wire being put on. to ground through capacitor 960 to form the return cherain of the current of this tone.



   Having been informed in this way that all local branch B circuits are in service, the operator

  <Desc / Clms Page number 61>

 failure to systematically test all connection circuits successively; it can free anyone who is blocked while not being used for a conversation.



  A connection circuit can be blocked without being used for communication when a calling line has become defective after communication has been established and therefore the line relay of the connector has not released when the calling subscriber has hung up his receiver, it can also be blocked if the calling subscriber neglects to hang up his receiver at the end of the conversation.



  * In order to carry out the supervision of the local connection circuits of office B, the attendant transmits a preliminary digit (the number "1" for example) then she transmits the number 1 several times which advances the SS supervisory switch of fig. 10 in different positions and establishes a direct connection with each of the junction circuits each time a digit 1 is transmitted and this until all circuits have been tested.



   When the preliminary digit 1 is issued, the tens digit "count" relays 922 and 923 pull as described previously and relay 923 pulls to place the SS supervisory switch solenoid under control of the relay. 913.



   At the same time the pulse which is emitted by the momentary release of relay 913 passes through the contacts of relay 914 and ends up in the upper winding of relay 952 through the inner lower contacts of relay 955 and the contacts. inner lower parts of relay 851.

   Relay 952 locks to wire 930 grounded at its lower middle contact, it opens the blocking circuit of relay 907 at its lower internal contact (relay 908 not being pulled at this time); at its lower contact it prepares the control electromagnet circuit of the supervision switch SS associated with the equipment unit CE1

  <Desc / Clms Page number 62>

 common of fig. 10; at its upper contact it cuts off the circuit through which the busy tone current was sent from wire 858, which cuts off the transmission of that tone.



   Each time the digit 1 is emitted subsequently, a pulse is sent by relay 913 through the lower contacts of relay 914, the lower contacts of relay 952 in multiple with the lower contacts of released relay 907, the contacts bottom of relay 925 to lead to the SS supervisory switch control solenoid. The operation of the SS switch solenoid moves the negative and positive RC brushes of the switch forward one step and the negative, positive and C brushes make the connection through the contacts and conductors of the bench with the wires. negative and positive 621 and 622 and with wire 723 of the forced release.



   If it is assumed that the attendant has not found a conversation in progress in the connection circuit of figs. 6, 7 and 8 and that this connection circuit is maintained by a calling line (the FPL line of fig. 3 for example) either because the line has become defective after a communication has been established, or because If the calling subscriber has neglected to hang up his receiver, the attendant can force free the connection circuit.



   To do this, it momentarily operates the key K2 of FIG. 12 which momentarily balances the current flowing in the junction circuit OT1 and attracts the differential relay 912. The relay 912 momentarily applies a ground through the brush C of the supervision switch SS and the pin of the bank on which it is engaged, to wire 733 of the LOC connector.



  The relay 708 therefore draws through the wire 733 to remove the earth from the wire 723 and cause the release of the connection circuit, as has been described previously. The operator can then continue the control operations until she has inspected each of the local connection circuits by freeing those she finds blocked by a defective line.

  <Desc / Clms Page number 63>

 



   -As soon as a connection circuit has been made free, the earth is removed from wire 861 which causes the disengagement of distributor D from the occupation position of all connection ports and causes the release of the relay 851. The relay 852 however remains attracted in the blocking circuit borrowing the wire 930 earthed. The moment the next pulse is emitted to the contacts of relay 913 (either by sending the next digit 1 or following the release), relay 854 attracts through contacts of relay 955 and contacts of relay 851 which is released now. When it attracts, relay 854 opens the blocking circuit of relay 855 at its upper contacts, which therefore releases.



   When she has finished the control operations, the operator of office A returns the response key K1 in fig. 12 to the normal position, which opens the bridge placed at the terminals of the wires of the junction circuit CT1 and allows the release of the common equipment CE1 unit. When earth is removed from wire 930 at relay 916 contacts the blocked relay 852 can drop as well as the CE1 unit relays of the common equipment.



   The SS supervision switch is returned to the normal position when the relay 916 releases and closes the solenoid release circuit through the supervisory switch brush via the engagement contacts and the switch contacts of the switch. 'electro magnet.



     At regular intervals, an operator from office A can check the local connection circuits by lowering the answer key K1 to put the trunk circuit OT1 into service when no call is made on this circuit. At the moment, relays 908,

  <Desc / Clms Page number 64>

 906 and 907 are inactive and the negative and positive brushes of the SS supervisory switch remain connected to the release wire of the OT1 junction circuit through the trailing coil 947, and they are not disconnected by the relay 907 as is. passes normally when a call is answered. In addition, with relay 907 not attracted, its lower contacts prepare the SS supervisory switch electromagnet circuit.

   This circuit is established as soon as the attendant transmits a preliminary digit and therefore causes the pulling of relays 922 and 923 "counting" of the tens digit.



   The manner in which an alarm is transmitted from the remotely controlled office B to the control office A through the trunk circuit OT1 will be described below. In the MG group in fig. 9, the load board is represented by rectangle 862. Contacts 863 are mounted on the power board, they close when an abnormal condition arises in the office, such as blown fuse, blocked load device, etc. When contacts 863 close relay 853 draws through contacts of relay 854.



  At its upper contacts, relay 853 reverses the signal wires to prepare for the transmission of a signal coming from the inrush current generator wire through capacitor 859 at the time of the operator's response, to his lower contacts relay 853 closes the circuit of relay 855 through its lower winding and the contacts of relays 908 and 916. When relay 855 attracts, the attendant is alerted, through the OT1 junction circuit of the manner which has been described previously, and when it responds it knows that an alarm is sent because the signal given by the generator is applied through the contacts of the relay 853 attracted.

   When the connection is released, a pulse is given by relay 913 on wire 934 to attract

  <Desc / Clms Page number 65>

 relay 854 and block it through contacts 863. Relay 853 therefore releases.



   It has been provided that any of the trunk circuits could be taken out of service while leaving the other in service to handle all calls which are made by the remotely controlled office. This can be done either from office A or from office C. by sending a specific number to the connectors of office B. The deactivation and the putting into service of the junction circuit OT1 are controlled by relay 902, an identical relay. being provided in the common equipment unit CE2 to perform a similar function there. Terminal 81C associated with the top winding of relay 902 is identical to terminal C of the bank of any connector reached when number 81 is issued. Terminal 82C associated with relay 902 is the terminal which is reached by brush C of any connector when N 82 is issued.



   If we now assume that the number 86 is sent to a connector of the office A, the brush C of this one engages on the pin 81 shown or on a multiple thereof, which extends the earth to to the upper winding of relay 902. Relay 902 attracts dona and closes its blocking circuit through its lower winding in series with the resistor associated with it. At its lower contact, relay 902 closes the circuit of relay 901 which attracts and moves the "tap" wire from wire 961 to wire 961 'associated with the CE2 unit of common equipment.



   The deactivation can be carried out at a time when a call is on hold at the CE1 equipment. relays 903 and 904 had to be provided, the function of which will be explained below; At the upper contacts of relay 902, the circuit of relay 903 closes. Relay 903 attracts and closes the cir- cuit of relay 904. Relay 904 attracts and locks at the switches of relay 902 which disconnects relay 903 which releases after a certain time. Relay 904 remains engaged and the relay

  <Desc / Clms Page number 66>

 
903 remains released until relay 902 can also release.

   At the upper contacts of relay 903, the circuit of relay 914 closes; as a result, the relays 914 and 916 successively attract and release successively, later, when the relay 903 drops. As a result of the action of these relays on each other, a pulse is transmitted, as explained previously, over wire 954 to cause the attraction of a relay such as relay 708 in the local connector. LOC and to free the junction circuit which was blocked. The calling subscriber can hang up his receiver and then pick it up to send a new call which will then be passed through the trunk circuit remaining in service.



   The junction relay OT1 to the CE1 unit of the common equipment can be put back into service by issuing the N 82.



  As a result, the brush of the connector used will connect to pin 82C of fig. 10 or a multiple thereof which extends the earth to the junction point of the lower winding of relay 902 and its associated resistor. This earth short-circuits the lower winding of relay 902 and allows the latter to be released by opening its blocking circuit. The rail 904 releases as well as the relay 901.



   The CES unit of the common equipment and the junction circuit OT1 which is associated with it are put out of service when the N 83 is sent, they are put back in service when the N 84 is sent. This operation is carried out through terminals 83 and 84 or the multiple thereof.



   The manner in which local service connections are established for lines leading from office A to lines terminating at office B will be explained below. If we assume that a call is received at the manual table in office A and that this call is sent by a local subscriber who wishes to be put in touch with a subscriber in office B, the operator in,

  <Desc / Clms Page number 67>

 push its call card (not shown) into jack J1 in fig. 11. Relay 110 draws through the barrel terminal of jack J1 to disconnect the upper winding of relay 1102. No supervision circuit is connected to the terminals of the head and neck wires of the jaok J1. because it is assumed that office A is a local battery office.



     At its upper contacts, relay 1101 bridges polarized relay 1105 at the terminals of the capacitor associated with the right windings of the translator coil 1100 which closes a call bridge at the terminals of the LST junction circuit for local service. Relay 1105 does not attract at this time, the direction of the current in its winding not being favorable to attraction. The LC3 line circuit in fig. 5 is identical to the LC1 line circuit, so a finder such as the finder in fig. 6 connects to an LST junction circuit for local service via terminals 551 or to the multiple of these.

   The call made on the LST trunk for local service is handled at the remotely controlled office in the same manner as a call made by a local subscriber line; a control operator from office A is notified through one of the two trunk circuits OT1 or OT2 to receive the desired number and to control the establishment of the connection to office B.



   The established connection is cut when the operator of office A removes the plug from jack Jl which allows relay 1101 to return to idle and cuts the bridge placed on the wires of the LST junction circuit for local service.
As stated previously, the LST junction circuit for local service of figs, 5 and 13 is one of the 4 junction circuits for local service intended for establishing communications between offices A 'and B. At the office B, These 4 junction circuits are accessible from the neighboring contact sets in the same level of the connector banks.

   The number that is assigned to this group of circuits

  <Desc / Clms Page number 68>

 jono.tion is composed of two digits which are necessary to bring the brushes of the connector in front of the desired level and to turn these oi until they come into engagement on the first junction circuit of the group which is assumed to be the LST junction circuit. The terminals 550 are those of the bank of one of the connectors. In addition, the trunk circuit group number contains a number (such as the number
2) which must be sent to cause a group station selector such as the PSI selector in fig. 8, for sending the inrush current which should alert the operator to office A.



   If the first junction circuit of the group is free, the communication is established in the same way as a communication intended for a local line. On the other hand, if the first junction circuit is busy, a busy signal is transmitted to the control operator and to the calling subscriber via the equipment unit. common in service and the attendant must send an additional "1" digit to cause the brushes of the connector to advance on the junction circuit which follows in the group; if the next junction circuit is busy, the attendant repeats sending the additional number "1" and causes the brushes to advance on the next junction circuit until they have all been tested.



  As soon as a free trunk circuit is reached, the busy tone is removed and the connection can be established with this trunk circuit. The circuit arrangements which govern the controlled advancement of the connector brushes when the first trunk circuit of the group is busy have been previously described in connection with multiple line service for subscribers in office B.



   The supervision operations which are necessary for the establishment of calls on the trunk circuits for local service between offices B and A are detailed.

  <Desc / Clms Page number 69>

 below in the discussion that will be made on the re-establishment of calls from prepaid sets.



   As explained previously when dealing with the junction diagram of fig. 2, the lines of the prepaid stations connected to office B provide outgoing service directly to office A via the selector switches. junction for local service, such as the LST junction circuit, A prepaid service line is shown in fig.2. It extends from the prepaid station to the LC4 line circuit whose LS preselector has access to the LST trunk circuit for local service and to the other trunk circuits for local service which extend between offices A and B. The line circuit L04 as well as the pre-selector LS which is associated with it is shown in the circuit of fig. 19.

   Referring now in particular to FIG. 19, a description will be given of the operations which take place when a subscriber to the prepaid station 1600 of the PSL line makes a call;
When the receiver is picked up at the prepayment station 1600, the relay 1602 draws through contacts of the relay 1601 and closes the circuit of the relay 1608 of the time device comprising the relays 1608 and 1609, through its lower contacts and them. contacts of relay 1606. By this operation, the device is put into service in time to send an alarm on wire 1611 in the event that the preselector is unable to find a free junction circuit within the time allocated by the device in time 1608 to 1609.



  This period can be set between one and three seconds, depending on the setting of relays 1608 and 1609.



   Relay 1608 has a weighted contact which is controlled by the armature and which vibrates for a certain time.



  During the vibration of relay 1608, relay 1609 cannot attract. If the preselector has not found a free line until the moment when the vibration has ceased in principle, the relay

  <Desc / Clms Page number 70>

 1609 attracts and blocks through the contacts of relay 1603, it closes an alarm circuit through wire 1611 and the contacts of relay 1604. In addition, relay 1609 disconnects the control solenoid 1610 from its inner top contacts, to its top contacts, it connects wire 1612 through contacts of relay 1604, to the calling line to inform the calling subscriber that the line is busy. This connection is established through a small capacitor limiting the value of the current as has been shown.



   Assuming now that the LS preselector is able to find a free trunk, the search operation is performed in a very short time and before the device has. time 1608 to 1609 had time. to achieve the operation as described above.



  The junction selector search operation is performed as follows:
When relay 1602 attracts as described above, it also closes the circuit of relay 1603 through its internal contacts. Relay 1603 places an earth on wire 1617, it closes the search circuit for control electro 1610 through contacts of relay 1609.

   The upper inner contacts of relay 1603 and contacts of relay 1604 to allow switch LS to search for a free junction circuit in the event that the one on which brushes 1651 are located is already in service; closes the circuit of relay 1604 in series with the control solenoid 1610 to become active when a free junction circuit is found; at its upper contacts, it disconnects relay 1601 and connects wire C which is associated with it to earth to keep the line of the prepaid station against any untimely seizure at terminals 1650 or to a multiple thereof.



  When the LS preselector is located a --- circuit

  <Desc / Clms Page number 71>

 junction free for local service, the junction circuit LST in fig. 5, for example, no further operation of the electromagnet takes place and the relay 1604 attracts in series with the electromagnet 1610.

   When relay 1604 attracts, it disconnects alarm wire 1611 to prevent further sending of an alarm; it bypasses the upper internal contact of relay 1609 to its upper internal contacts to effect an interrupt in its own circuit when relay 1609 attracts; it opens the test circuit of the electromagnet 1610 and applies a protective earth directly to the brushes 16510; it removes the guard function performed by the upper contact of relay 1603; it extends the conversation wires of the PLS line through the capacitors 1615 and 1616 to the negative and positive brushes le'51 while at the same time opening at an additional point the circuit for sending the current of the busy tone coming from wire 612.



   Applying a positive to 1651 C brushes has the effect of extending the earth through conductor C to the LC2 line circuit breaking relay in fig. 5 corresponding to the 302 breaking relay of the LC1 line circuit. of fig. 3. This cut-off relay attracts to release the LST junction circuit of the LC3 line circuit.



   When relay 1604 attracts, it sets up the circuit of relay 1605, which had been prepared earlier at the middle contacts of relay 1602, through contacts of relay 1606. Relay 1605 therefore draws to transfer negative brush 1651 to the common wire. call 1614 in order to transmit the ringing current on the LST trunk circuit for local service to office A, a return to earth circuit being given through the middle contact of relay 1605 and the brush, positive 1651.

   At the same time, the relay 1605 extends the common wire 1604 for sending the inrush current through the capacitor 1616 and the resistor 1609.

  <Desc / Clms Page number 72>

 to earth through the top winding of the relay
1606. If we observe that wire 1614 is one of the wires to which the inrush current is applied directly by the generator of the ringing current, we can immediately see that the relay 1606 draws only after the machine of call or generator started. Relay 1606 therefore works as an automatic delay device to allow the calling machine to start before it cuts the circuit of relay 1605.



   When relay 1606 attracts, it closes its blocking circuit through its lower winding and cuts the circuit of the delayed relay on release 1605, which allows this relay to release after a short time and thus finish sending the signal. inrush current. Applying the inrush current given in this way is called a "ringing".



   Relay 1606 also opens the circuit of relay 1608, this release takes place under normal conditions before relay 1609 has had time to attract; it connects relay 1607 so that it can attract when the attendant answers; it connects wire 1613 giving the special tone to prepaid stations through the current limiting condenser and terminating at 1651 brushes via relays 1609. The tone applied to wire 1613 is a characteristic tone, used to inform the user. operator that a prepaid line has made a call. This tone is applied until the attendant answers and for a short interval as described later.



   In office A, the application of the inrush current carried out, as has been said above, has the effect of attracting the relay 1102 of fig. 3, the transmitted current is induced through the windings of the coil translator 1100. The relay 1102 closes the blocking circuit which passes through its lower winding to its internal contacts; at

  <Desc / Clms Page number 73>

 its lower contacts, it closes the circuit of the call lamp 1121.



   When the attendant at desk A responds when she sees that call lamp 1121 comes on (by inserting the response plug of a cord circuit into jack il) and that relay 1101 attracts and connects relay 1105 in circuit, the relay 1105 attracts because the conversation wires are reversed at the negative and positive terminals 550 of the connector and their multiple which causes the reversal of the current flowing through the supervision relay, the current therefore circulated in one direction reverse of the one it had when the call was made through the LST trunk circuit in office A. When relay 1105 pulls, it closes the circuit of relay 1104 which closes the circuit of relay 1103.

   The purpose of the operation of the relays 1103 and 1104 is to give an end signal to the attendant as will be explained later;
In office B, relay 1607 attracts when the attendant answers, it closes the circuit of relay 1608. The special tone at prepaid sets which is applied to the conversation circuit and which comes from wire 1613 is heard by the attendant. from office A as well as by the calling subscriber.



   This tone continues to be heard until relays 1608 and 1609 have drawn successively.



   The 1609 relay disconnects the 1613 tone wire when it attracts and the conversation can be established between the calling prepaid set and the operator of office A who can therefore pass the call as the subscriber of the prepaid set on longed for.



     It has been assumed that the 1600 prepayment station is equipped with a boot intended to receive the change, separate chutes being provided for coins of different values, each channel being provided with a characteristic gong or with any sound device which emits a sound of sufficient intensity when a coin falls into the boot

  <Desc / Clms Page number 74>

 so that the attendant can see it by the sound transmitted into the microphone of the prepayment set.



   When the subscriber of the prepaid station hangs up his receiver at the end of the conversation, the relay 1602 releases and returns the relays 1603 to 1609 to idle, which frees the line circuit. Disconnecting relay 1607 when relay 1606 releases has the effect of releasing relay 1105 at desk A.



   Relay 1105 allows relays 1104 and 1103 to release successively. During the interval required for the relay 1103 which is delayed on release to release the two poles of the battery powering the office are connected through the left windings of the translator coil 1100 to the head and neck wires of the J1 jack , to supply current to the supervisory signal which is assumed to be located in the cord circuit being used.



   When the attendant removes the cord circuit plug from jack J1, releasing relay 1101 has the effect of opening the control bridge placed on the LST line through relay 1105. It has been pointed out previously that devices Special arrangements had been made so that office B could be controlled remotely by office C while the trunk circuits OT1 and OT2 were taken out of service. In addition, it was pointed out that it is advantageous to use, as a back-up junction circuit, a pair of wires which do not take the same route as the wires of the normal junction circuit because there is less chance that the wires of the diverted channel be taken out of service at the same time as the wires of the normal channel.



   In order to carry out the transfer from the control center, an operator from office A or from office C sets the transfer digit 85 to any of the con-

  <Desc / Clms Page number 75>

 nectors of office B. when the number 85 is emitted, the brush C of the connector used is brought to pin 85 of fig. 9 or to a multiple thereof which closes the circuit of the upper winding of relay 856 .

   When relay 856 pulls, it closes its own blocking circuit via resistor 857 At its bottom armature, relay 856 grounds switching wire 944 'causing the relay to pull in. the CES unit of the common equipment, In addition, the relay 856 disconnects the outgoing conversation wires associated with the common equipment unit CE1 from the wires of the OT1 junction circuit and transfers these to wires 1437 and 1428 of the interurban line TL2 of fig. 16 and 14.

   At the same time, relay 856 connects an additional power supply bridge to the terminals of the OT1 junction circuit pads to allow this circuit to be tested more directly and to allow relay 1005 to draw through the circuit. junction when the release has been performed.



   In addition, the 856 relay disconnects the wires 1424 and 1425 from the wires 1427 and 1428 of the trunk line to leave it free for office B, to carry out the control operations, at its highest contact it places a earth on wire 1428 to protect the local end of the interurban line EL2 from being taken through the connectors at office B.



   In order to effect the transfer to office C, the key K3 is actuated to pass the wires of the trunk line TL2 of the normal equipment shown in fig. 14 to the equipment of FIG. 15 which is similar to that shown in FIG. 12.



   When the operation of the remotely controlled office B is no longer under the control of office A, relay 856 drops because the release number 86 has been sent to any of the connectors in office B. , the brush C of the connector in service places a positive on the terminal

  <Desc / Clms Page number 76>

 86 C of fig. 8 or a multiple thereof, this extends a positive towards the junction of the lower winding of relay '856 and resistor 851 which bypasses the lower winding of the relay which releases and disengages the IEC unit from the common equipment of the TL2 trunk line of FIG.

   16 and places this CE1 unit under the control of the trunk circuit OT1 leading to office A while allowing the control relay of the unit CES (corresponding to relay 901 of CE1) to release to allow calls to be passed through. the CE1 unit of the common equipment.



   The operations which are carried out when extending the connection of a calling line from office B to the long distance table in office C in FIG. 14 will be explained below. For this purpose, it will be assumed that the subscriber of set 300 has picked up his receiver, this has the effect of connecting the calling line to the connection circuit of FIGS. 6, 7 and 8 and the common equipment CE1 of fig. 10 and 11 are activated to call the control operator of office A through the trunk circuit OT1.



   The trunk lines that connect Office B to Office C are accessible at connectors in Office B through the 10th level. The first of these lines being reached when the N 01 is emitted, therefore, the first number emitted by the operator is the number "C", it follows that 10 pulses are sent on wire 956 through the contacts of the relay 703 attracted and up to the ascent electromagnet 716 of the local LOC connector.



  At the same time, the brushes 700 are brought in front of the 10th level of the bank contacts. The springs 721 and 724 of level "0" are therefore brought into their working position.



  Springs 723 prepare the circuit of the upper winding of relay 705 through pilot wire 959; the springs 721 prepare the circuit of the lower winding of the relay 710 and the springs 724 disconnect the relay 711.

  <Desc / Clms Page number 77>

 



   In the CE1 common equipment unit; the relays
922 and 923 of the tens digit are drawn as described above; relay 923 transfers the pulse wire from wire 956 to wire 957.



   When the second digit, the digit l, is emitted, the pulse is transmitted through the wire 957 to the electromagnet 717. The brushes 700 are therefore 'brought' to the first group of bank contacts. of the 10th level which are assumed to be the group of contacts 1450 of fig. 16 or multiples thereof associated with the outgoing junction circuit CTC. If the TL2 junction circuit, associated with the first group of debank contacts, is in service, an earth is connected to terminal C of this group. In this case, relay 917 attracts and prepares its own blocking circuit which closes when relay 919 releases. In this case, a busy tone is applied to the upper contacts of relay 917 to inform the operator calling that the line is busy.



   For the sake of uniformity of the numbering system, an additional digit such as the digit "2" is assigned to the trunk group terminating at office C when this digit is transmitted, two pulses are sent over the common 934 pulse wire. , they pass successively through the contacts of relays 923 and 924 attracted (the lower coil of relay 924 is fed in multiple with the lower coil of relay 917) through contacts of relays 926 and 928 and of wire 958 to end at the solenoid 743 of the SP1 selector of the grouped stations.



  The selector brushes are therefore brought to the second group of bank contacts, but the setting of the selector is not important for the moment.



   Relays 925 and 926 draw successively under the control of relay 919, relay 926 disconnects the lower winding of relay 924 since relay 920 has no

  <Desc / Clms Page number 78>

 attracted at this time. Relay 924 therefore releases and transfers wire 934 to wire 957 again to allow further advancement of the brushes 700 of the LOC connector under the control of the rotation electromagnet 717. The operator can now transmit the number " 1 "one or more times for the purpose of advancing the brushes 700 until the last trunk line in the group is reached or until a free trunk line is encountered.



  When a free trunk line is reached, relay 917 releases, the lower winding of relay 921 is fed through wire 960 and brush 7000 in series with the relay winding connected to wire C of the called trunk line. Relay 921 connects its top winding to wire 935. Therefore, the top winding of relay 924 is fed in multiple with the top winding of relay 921. Wire 934 is disconnected from wire 957 but it is not connected. back to wire 958 because the latter is now interrupted at the upper contacts of relay 926. At the same time, relay 929 attracts in multiple with the upper windings of relays 921 and 924 through contacts of relay 926 due to the attraction of relay 921 which closes its blocking circuit to its upper winding.

   The operation of relay 929 has the effect of attracting relay 705 as will be shown later.



   The operations which take place when the first trunk line of the group is busy having been explained, it will now be assumed that the first trunk line of the group (line TL2 in fig. 16) is free when sweeps 700 of the LOC connector s' stop on contacts 1450 because the number transmitted is 01. In this case, relay 921 immediately attracts at the end of sending the 2nd digit l, this circuit includes its lower winding

  <Desc / Clms Page number 79>

 and wire 960 from the contacts of relay 703 attracted, contacts of relay 706, brush 700 0, terminal 1450 C, wire 14210 of contacts of relay 1405 and the top winding of relay 1406.

   Relay 1406 draws into this circuit to disconnect wire 1423 C from the lower winding of relay 1405 and connect this to earth to keep terminals 1451 and the multiple of these in the trunk connector bank. .



   The positive of wire 1421 is extended through the upper contacts of relay 1606 to relay 1411 which causes the attraction of this relay and consequently releases the wires 1424 and 1425 from the trunk line TC2 of FIGS; 17 and the through contacts of relay 1409, to bring them to the windings of the translating coil 1400.



  Relay 1411 also closes the circuit of relay 1410.



  Relay 1409 attracts and closes the circuit of relay 1410; the result is that the relay 1410 attracts and blocks at the contacts of: relay 1411, at the same time it opens the circuit of the relay delayed on release 1409 and allows the latter to release. Relay 1409 therefore attracts momentarily, to send the inrush current to wires 1424 and 1425 of the TL2 trunk line to alert the operator in office C.



   Note that the central office generator is kept running at this time because relay 914 keeps wire 948 grounded.



   In the common equipment unit CE1, the operation of relay 921 has the effect of attracting relay 924, the circuit is extended to wire 958 on which the two pulses of digit 2 for selecting the group station are transmitted when this digit is transmitted;
At the end of the transmission, from the group set selection digit (added to the N for more uniformity), relay 926 attracts under the control of relay 925, which is in turn controlled by relay 919. When the relay 9S6 attracts it closes the circuit of relay 929 as it was said above.

   When

  <Desc / Clms Page number 80>

 the relay 929 attracts, it applies a negative polarity to the wire 959, through the resistance which is associated with it; by this operation, a circuit closes which borrows the wire 959, the contacts of the relay 703 attracted; the actuated springs 723 of level 0, the upper winding of the relay 705 for grounding.



   When relay 705 pulls, as stated above, it connects relay 708 to brush 700C, it closes an additional circuit to keep relay 707 drawn independently of relay 706; it disconnects the overflow wires 621 and 622 from the windings of the relay 706 and extends them directly to the negative and positive brushes 700, to allow the line relay of the trunk circuit put in service to be maintained directly across the line appellant. In addition, relay 705 prepares its blocking circuit through its lower winding, to its lower contacts which close after the operation of relay 702.



   When the attendant releases the OT1 junction circuit and the common equipment CES unit, the application of a ground to wire 955 through the contacts of the attracted relay 921 has the effect of attracting the relay 702 through the contacts of relay 703. In addition, that it is blocked with the wire 623 put to the ground, in multiple with the winding of the relay ce 701 and of / that it disconnects the winding of the relay 703 and applies an earth direct to the brush 700 C, the relay 702 closes the blocking circuit of the relay 705 through its lower winding.

   This circuit extends from the 734 grounded wire through the contacts of the relay 710, the contacts 704, the contacts of the drawn relay 702, the contacts 721 of the level 0, the contacts 722 to the Winding. of relay 705, A branch of this circuit extends through the lower winding of the drawn relay 705 to the winding of the relay 710. The relay 710 therefore attracts and locks directly to the wire 734 set.

  <Desc / Clms Page number 81>

 earth thereby closing a multiple circuit through the lower winding of relay 705 and the lower contacts of that relay.

   Relay 710 disconnects earth from wire 736 to prevent unwanted operation of the inrush current switch. as a result of the switching operation which is clamped to the two highest contacts of the relay 705 of the local connector LOC, the relay 402 of the outgoing junction circuit OTO2 draws through the calling line the wires 1419 and 1420 and the left winding of the translating coil 1400. The relay 1401 works when the relay 1402 attracts and prepares the forced release circuit through the wire 1422, this circuit becomes active in the event that the operator at office C does not respond and the 'subscriber calling his receiver, without having received an answer.



   In office 0 of Fig. 14, the momentary application of the ringing current causes the momentary pull of relay 1409, as previously explained.



  This has the effect of attracting the sensitive relay 1204. The relay 1204 is blocked by its lower winding connected to earth; to the contacts of relay 1203, it attracts relay 1205 to light lamp 1206. When the attendant answers, when call lamp 1306 comes on, she inserts the plug of a free cord into the jaok J2, relay 1202 pulls into the barrel circuit of jack J2 to close the circuit of relay 1201 through its lower winding.

   Relay 1201 thereby closes the circuit of the lower winding of relay 1203. Relay 1203 opens the blocking circuit of relay 1204; it opens the circuit placed at the terminals of the upper coil of relay 1204, It disconnects relay 1202 and prepares its blocking circuit for the barrel of jack J2.



  This circuit closes as soon as relay 1202 releases. When relay 1202 releases, it opens the circuit of the lower winding of relay 1201, but relay 1201 remains attracted by the effect of its upper winding and through them.

  <Desc / Clms Page number 82>

 J2 jack head and neck contacts.



   At its upper contacts, relay 1203 places a shunt across the capacitor associated with the left windings of translator coil 1200, which causes direct current to be sent on trunk line TL2 through the windings of relay 1408. , in series with the differential windings of relay 1407 and the straight windings of the translator coil 1440. Relay 1408 draws in this circuit, but relay 1407 does not. Relay 1408 prepares a special blocking circuit on itself at its upper contacts. He attracts relay 1400 to his lower contacts; at its lower contact, it opens the forced release circuit at one point and closes the circuit of relay 1404 through the contacts of relay 1405.



  Relay 1404 attracts and closes its contacts, but this has no effect because relay 1403 is not attracted at this time.



   The long distance operator in office C can now complete the call as usual.



   Relay 1408, now relay 1400 attracted, releasing relay 1402 does not have the effect of applying earth to wire 1402. Therefore, the calling subscriber can call back the operator by shaking the fork of his set without release the local LOC connector. When relay 1402 releases and when relay 1401 also releases, the circuit of relay 1409 momentarily closes through contacts of relays 1408, 1401 and 1402. Relay 1409 initiates an inrush current on interurban line TL2 for call the operator back from office C. Note that relay 1409 closes the blocking circuit of relay 1408 through its upper winding to prevent releasing of this relay during momentary application of ringing current.

   The relays 1402 and 1401 pull again when the fork contacts are closed at the calling station.

  <Desc / Clms Page number 83>

 



   When the calling subscriber hangs up his receiver at the end of the conversation, relays 1402 and 1401 release, Relay 1409 momentarily attracts as said previously - this time to give the operator of office 0 a signal
 EMI83.1
 end of oommunioation.



   When the attendant at desk C pulls out the plug from her jaok J2. the relays 1201 and 1203 release; relay 1203 opens the bridge placed across the TL2 trunk line, which allows relay 1408 of the OTC2 junction circuit to release. When relay 1408 releases, it opens the circuit of relay 1400 and closes the forced release circuit through contacts of relay 1400, for a time long enough for that relay to release after its circuit has been opened. The forced release oirouit borrows the wire 1428.EG, the brush 700 EC, the contacts of the relay 705 to lead to the relay 708. The relay 708 attracts under the action of this momentary impulse.



  The relay 708 being delayed in operation remains attracted, for a long enough time, to allow the relay blocked in the LOC connector and the finder F1 to release.



  The oheroheur and the connector are returned to the normal position under the action of their release electromagnet. In the OTC2 junction circuit in Figure 16 when the local connector removes the ground from wire 1421, relays 1406, 1411, 1410 and 1409 release. It should be noted in particular that the local connection is released automatically when the operator cuts the connection, whether the line and release relays 1402 and 1401 have released or not. This way, a faulty local line cannot keep a trunk line out of service.



   Referring to Figures 1 and 2, it can be seen that a long distance operator in office A can establish a long distance call to a subscriber in office B by

  <Desc / Clms Page number 84>

 via the TL1 trunk line, using the TC1 connector in fig. 2. On the other hand, it can be seen that the connector TC1 can be used to establish a connection through office B to office C via a trunk line such as line TL2.

   In order to explain the characteristics of the OTC2 junction circuit in fig. 16, we will now assume that the operator in the office
A has put into service the TL1 trunk line in figs, 1 and 2 and has sent the trunk group number from office B to office C. It will be assumed, moreover, that the TL2 trunk line is free and that the TOI long distance connector in fig. 2 therefore seizes the line TL2 at terminals 1451 via the outgoing junction circuits OT02 of FIG. 16.



   When terminals 1451 are entered and a ground is applied to wire 1423 C, the lower winding of relay 1405 is energized through contacts of relay 1406. Relay 1405 places a ground on wire 1421 C to keep the circuit. junction against any intrusion from other local connectors.



  It also attracts relay 1403 to disconnect the windings of relay 1402 and to prepare a supervisory bridge across wires 1419 and 1420 through contacts of supervision relay 1404. In addition, relay 1403 attracts the relay. 1411 which, in turn, attracts relays 1409 and 1410, as described previously, to cause the momentary sending of the call current on the interurban line TL2, with the aim of alerting the office operator c. when the operator at office C answers, relay 1408 attracts as described above;

   at this time, when relay 1404 attracts after relay 1408 has operated, it closes a bridge across wires 1418 and 1420 through the contacts of the attracted relay 1403, which attracts the relay of the trunk connector TC1 , in fig. 2, corresponding to relay 1506 of the intercity connector TC2,

  <Desc / Clms Page number 85>

 of fig. 17, to attract the relay identical to relay 1505 which prepares the operation of the relay identical to relay 1501.



   If we suppose that the interurban operator of office 0 wishes to call back the interurban operator of office A, she momentarily operates the key K4 of fig. 14, which causes the relay 1407. The relay 1408 remains attracted, but the relay 1404 releases to open the supervision bridge placed at the terminals of wires 1419 and 1420, which causes a momentary attraction of the connector return relay, TOI which corresponds to relay 1501 of the long distance connector TC2 in fig. 17. The callback relay momentarily starts ringing current on the TL1 trunk line in Figures 2 and 1 to call back the attendant at office A.



   When the connection is to be released, the TC1 connector releases following the opening of the TL1 line at office A. When the outgoing junction circuit CTC2 in fig. 16 is released at terminals 1451, relays 1405 and 1403 release and relay 1403 allows relays 1411, 1410 and 1409 to release.



   When the long distance operator of office C receives a long distance call which must be extended to a line in office B, she can establish this communication through one of the long distance lines connecting office C to office B of long distance line TL2, by example. When the attendant inserts the plug of a cord circuit into the J2 jack of fig, 14 to activate the TL2 trunk line, the relay 1202 attracts and disconnects the upper winding of the relay 1203.

   When the plug has been fully inserted into the jack, relay 1201 draws through the head and neck contacts of the jack and closes a temporary blocking circuit through its lower winding and the contacts of relay 1202, finally. , it closes the circuit of the lower winding of relay 1203, The relay 1203

  <Desc / Clms Page number 86>

 therefore attracts and prepares its blocking circuit through the barrel of the J2 jack as soon as the relay 1202, delayed in operation, releases because it has been disconnected by the relay 1203.



   At its upper contacts, the relay 1203 closes a control circuit through the trunk line TL2 via the left windings of the translator coil 1200. This circuit extends through the wires 1416 and 1417, the right windings of the trans- latrioe coil 1550 to terminate in the windings of relay 1502 of the trunk connector TC2. Relay 1502 pulls relay 1503 and feeds the upper winding of relay 1504 through contacts 1525.



  When relay 1523 attracts to its upper contact, it grounds wire 1418, which attracts relays 1405 and 1406 of the outgoing junction circuit OTC2. This relay extends the earth to the accessible terminals C of the trunk and local connectors, respectively, to prevent the seizure of the trunk line OTL2 in any of these selectors. Relay 1404 prepares the circuit of the electro-ascension 1528 and its blocking circuit through its lower winding.

   It moves the circuit of the lower winding of relay 1502 so that it includes wire 1525 of the prompting tone to be transmitted and a corresponding signal is transmitted through the windings of the relay. 1502 to the calling operator in office C to inform her that the interurban line is in working order and that she can send the requested number.



   It should be noted that the arrangement of the equipment shown in fig. 14 is established by supposing that two interurban positions are provided at, office c; they serve the calls which have passed through the TL trunk trunk. The K5 disk key is located so

  <Desc / Clms Page number 87>

 so that it can be reached from one of the two positions.



  This key can be lowered to the left to associate disk 1301 from position 1 to trunk line TL1 and it can be lowered to the right to associate disk 1302 from position 2 to trunk line TL2.



   The KS disk olé is maneuvered in the desired direction to associate the disk of the operator who calls to the TL2 trunk line. Then the attendant transmits the digit of the desired number and returns the K5 disk key to the normal position.



   When the first digit has been transmitted, the 1502 relay will momentarily release a corresponding number of times. Each time it releases the relay 1502 closes the circuit of the ascending electromagnet 1528 through the contacts of the attracted relay 1503 and the contacts of the relay 1504. As a result of the operation of the electromagnet of ascent, the brushes 1500 are raised step by step until they come to be placed in front of the desired level of the bank contacts. Shaft springs 1537 open the initial supply circuit of the upper winding of relay 1504 which however does not release until the end of the sending of the pulses, at which moment it transfers the pulse circuit. from the ascent electromagnet 1518 to the rotation electromagnet 1529.



  At the same time, releasing relay 1504 connects the circuit of the lower winding of relay 1502 to ground which disconnects wire 1525 from the invitation tone to transmit,
When the 2nd digit is output, the pulses are sent through the contacts of relay 1511 to the rotation solenoid 1529. Operation of the solenoid 1529 rotates the brushes 1500 on the contacts of the selected level until what they engage on the terminals of the line requested. Relay 1509 attracts in multiples with the rotating electromagnet when the first

  <Desc / Clms Page number 88>

 pulse is emitted. Since this relay is delayed on release, it remains attracted while the rotation pulses are sent.

   At its internal contact, relay 1509 attracts relay 1510, at its upper contact it disconnects relay 1500 C and the test winding of relay 1511 and transfers it to the winding of relay 1508. As a result, if the called line is busy, relay 1508 attracts and prepares its own blocking circuit, it also prepares the connection to the busy tone wire.



  When the relay 1509 releases, the electromagnet 1529 is therefore disconnected. At the same time, relay 1509 establishes the blocking circuit from relay 1508 to grounded wire 1418 (through the top contacts of release relay 1503).



  This blocking circuit includes contacts of relay 1511.



  When relay 1510 releases, a connection is made from the busy tone wire to the upper conversation wire; therefore, a busy signal to the calling operator is transmitted to inform him that the called line is busy.



   In the case where the called station has multiple line service, as described above, the operator can send an additional number 1 to cause the brushes 1500 to advance on the next line. On the other hand, if the call is intended for an individual line, the attendant removes the plug from jack J2 in fig. 14 and allows the release of the connection which has been partially established.



   If we now assume that the called line is free, relay 1508 does not draw when brushes 1500 stop. In this case, the brush 1500 C encounters a negative on terminal C of the called line, this closes the circuit of the test winding of relay 1511 through the contacts of relay 1509, this circuit is extended to earth through the contacts of relay 1508.

  <Desc / Clms Page number 89>

 



   When relay 1511 attracts, it hangs over the wire
1418, it transfers the pulse wire from the rotation electromagnet 1529 to the control electromagnet 1533 of the PS2 selector of the grouped stations; it prepares the relay 1512 circuit, it disconnects the relay 1508 from the test circuit, it opens the busy signaling circuit at its upper contacts at one point; he disconnected the positive and negative 1500 brushes to prepare the circuit for sending the inrush current,
In the case where the line called is one of those which have a single digit code (the code digit which is between 2 and 6) the next digit / is sent is the final digit. The brush 1531 prepares the circuit for sending the inrush current coming from one of the wires 1533 of the code generator.

   In this case, relay 1515 does not attract,
When relay 1510 releases when relay 1509 drops out at the end of sending the group station selection digit, relay 1508 draws again through contacts 1535 to prepare the electronic circuit. - release magnet 1534; it places a ground on wire 1524 through the contacts of relay 1507 and it extends common wire 1523 through contacts of relay 1511 to relay 1512. Relay 1518 pulls when the "tap" pulse is received, it is blocked on wire 1418, at the same time it opens its initial supply circuit.



   At its upper contacts, relay 1512 establishes the circuit for sending the inrush current, it borrows the contacts bridged by brushes 1531, the upper winding of relay 1507 to end in the negative wire of the line called through. the contacts of relays 1516, 1517, 1507 and 1511.



  The ringing current return circuit is grounded through positive brush 1500 and relay contacts 1511, 1507 and 1517.

  <Desc / Clms Page number 90>

 



   On the other hand, if the line called is a line with a two-digit code, two digits for selecting the group set must be sent. The first number is number 1. In this case, the brushes 1551 and 1332 advance only one step. When relay 1509 releases after having attracted following the sending of the pulse constituting the first selection digit of the grouped station, it closes the circuit of relay 1515 to its internal contact through the contacts of brush 1532. Relay 1515 attracts and closes its blocking circuit to its inner armature, to its upper armature, it disconnects the inrush sending wire from the contacts associated with brush 1531 and transfers them to the contacts associated with brush 1532 of the two-digit code.



  In addition, relay 1515, at its lower contacts, opens the circuit of relay 1508 at one point to prevent the attraction of this relay through the shaft springs 1534 following the release of relay 1515 following the release of the relay. 1509. In the current assumption, the next digit to be output is one of the digits 1 to 5. Brushes 1531 and 1532 therefore advance until brush 1532 bridges the desired group of contacts associated with wire 1533 of the code generator,
When relay 1509 pulls again when sending the first group station selection digit, a ground is extended until relay 1514 is wound up. This relay locks to wire 1418 at its upper contact. At its lower contact, it prepares the circuit of relay 1508 which closes when relay 1510 releases.



   The inrush sending circuit is established when relay 1512 draws when connected to wire 1523 through relay 1508. This inrush sending circuit extends from any of the wires. 1333 through the pair of contacts bridged by the 1552 brush, through the contacts of the

  <Desc / Clms Page number 91>

 relay 1515 attracted and from there, as described above, through the winding of relay 1507 to the called line of negative brush 1500. When the called subscriber answers, relay 1507 pulls in and locks on. wire 1518. It removes the earth from wire 1504. At its highest contacts it opens the inrush current sending circuit and closes the conversation circuit. At this time, relay 1506 draws into the loop of the called line and causes the pull of relay 1505 to prepare the circuit of relay 1501.



   When the communication is terminated and the called subscriber hangs up his receiver, releasing relay 1506 has the effect of transmitting an impulse to relay 1501 for a sufficient time to allow the release of the delayed relay on release 1505. Relay 1501 grounds the upper talk wire 1416 to keep relay 1502 engaged, it initiates inrush current on wire 1417 to office C to actuate the end signal in the trunk cord circuit.



   It should in fact be understood that the relay 1501 attracts in this way when the calling subscriber shakes his fork momentarily in order to call back the operator.



   When the relay 1501 releases, it stops sending the inrush current and puts the relay 1502 back under the control of the TL2 trunk line. When the attendant cuts the connection established at the J2 jack, cutting the bridge placed at the TL2 trunk line terminals has the effect of releasing relay 1502. A pulse is transmitted at this moment to relay 1509, relay 1510 attracts but without effect. Note that relay 1508, having drawn, as described above through shaft springs 1555, keeps the electromagnet circuit open.



   When relay 1503 releases and removes, at its contacts

  <Desc / Clms Page number 92>

 above, the ground of wire 1418, the relays 1515, 1514, 1511 and 1507 of the trunk connector and the celais 1405 and 1406 of the junction circuit exited OTC2 release. The release electromagnet 1530 attracts through the shaft springs 1526 to return the brushes 1500 to the normal position; The release solenoid 1534 draws through contacts of relay 1508 to return the group station selector to normal position, Relay 1508 releases when shaft springs 1535 open, when brushes 1551 and 1532 have returned in normal position.



   At this moment, it can be noted that the relays 1515, 1516, 1517 and the negative and positive wires of the generator 151S and 1518 are provided in the long distance connector TC2 for the same reason as that given previously for the relays 712, 714 and 715 as well as for the negative and positive wires of the generator 734 and 733 of the local LOC connector.



  Since the operation of the local connector LOC in the case of a call to a fully selectable trunk line has been described previously, a detailed description of the operation of the LC2 trunk connector in a similar case will not be given. .



   The manner in which office machine B operates to allow the called line to ring when that line is connected to the calling line will be shown below.



   All subscribers grouped on the same line are informed that there are other subscribers who are in the same situation as them. It is further assumed that when a subscriber wishes to call another subscriber connected to the same line as him, he informs the operator of this fact, at the same time as he gives him the desired number. The calling subscriber then hangs up his receiver to allow sending of the inrush current.



  Local LOC connector relays 706 and 707 drop but

  <Desc / Clms Page number 93>

 the connection is maintained by earth which is normally connected to wire 623 through contacts 702, 702 'and 708.



   In this case, the attendant does not send the tens and units digits of the requested number, she simply sends the revertive call digit 7 and 0, In the local connector LOC the issuance of the revertive call digits 7 and 0 has the effect of placing the springs 722 and 762 in their alternate position.



   When the brushes 700 reach position 70 the brush 7000 does not encounter a polarity indicating that the line. is free when it engages on the bench contact, because the wiring wires have been removed at contact 70 to avoid interference between the connectors in the case of revertive calls. However, contact 762 is closed at this time, it applies negative polarity to brush C, through resistor 763, in order to complete the circuit of relay 921 through the contacts of connection relay 703 and the wire. test 960, assuming common equipment CE1 is the one put into service. At the same time, the circuit of the lower winding of relay 705 closes through contacts of relay 704 and relay 710 to the grounded wire 734.

   Relay 705 now pulls in to disconnect incoming wires 621 and 622. From the portion of the talk circuit that runs between relays 706 and 709 through capacitors 729 and 730, it extends these to negative brushes and positive 700 in order to allow normal transmission of the inrush current from the brush 700 through the multiple of the bank to the incoming wires 621 and 622 and to the calling line. At its lower inner contact the relay 705 closes the circuit of the relay 707 to make it attract again and prepare a new blocking circuit necessary to keep the ground wire 623 / to the ground after the relay 702 has drawn.

  <Desc / Clms Page number 94>

 when the operator cuts off the call.



   The attendant, by sending the digits 7 and 0 for a reverting call, causes the PSI selector of the grouped set to be placed in position and the inrush current to be sent to the requested set.



   When the attendant cuts off the communication, relay 702 draws through wire 955 and connects wires 755 and 736 to start the bell switch and to pull relay 711 causing the inrush current to be sent. The subscriber is ringed because the inrush current is sent to the calling line through the contacts of the attracted relay 705,
When the calling subscriber picks up his receiver again or the called subscriber answers whichever operation is performed first, relay 710 draws inrush current into the sending circuit.

   When it attracts, in addition to closing its blocking circuit, to its lower inner contacts and opening the inrush current sending circuit, relay 710 at its lower middle contact opens. circuit passing through the lower winding of relay 705, this relay releases and again connects relay 706 to incoming wires 621 and 622. Relay 706 draws back into the loop of the calling line to close the circuit. blocking of relay 707 and keep this relay attracted so as to connect a ground to wire 623 until the end of the conversation.



   The connection is released in the manner previously described when both subscribers hang up the receiver and allow relay 706 to release.


    

Claims (1)

CLAIMS. EMI95.1 --------------------------- 1. A telephone system comprising a remotely controlled office in which the making of a call in the remote control office has the effect of activating an automatic switch and associating this switch with a unit of equipment. common taken in a group of two units, each of them being permanently connected to a line extending to a remote office, the common equipment unit put into service serving to put the automatic switch associated with it directly under the control exercised through this line, by an operator of the remote office. 2. A telephone system comprising a remotely controlled office in which the sending of a call to the remotely controlled office has the effect of activating an automatic switch and associating with it a free common equipment unit taken in a group. two units each permanently connected to a line going to a remote office to allow an operator from this office to control the setting of this switch, the arrangements being such that if both units of the equipment are in service making a call in the remotely controlled office cannot have the effect of activating an automatic switch. 3. A telephone system comprising lines to grouped stations which are called by a ring code and lines to grouped stations which are called by selective calls in which an automatic switch having access to grouped lines of both types is set. in position on the desired line by pulse trains and can receive additional pulses which have the effect of controlling the application of the appropriate type of inrush current on the line of the selected group station without affecting the position taken by the switch automatic. 4. A telephone system using final selectors having access to several lines with grouped stations in which the selector <Desc / Clms Page number 96> terminal is put in position by two series of pulses and can then receive additional pulse trains to operate a station selection equipment in the group without affecting the position taken by the switch, if the requested line is busy and if it is part of a set of lines having access to the same subscriber station; the switch advances step by step through the group until it has found a free line. 5. A telephone system comprising a remotely controlled office which can be associated with an attendant at a remote office when a line calls into the remotely controlled office, in which the release of the connection to the remote office is placed under. operator control, if the connection is released without the attendant having sent impulses, which occurs if it is a false call caused by a faulty line, it is automatically bet on 'fault. 6. A telephone system as claimed in claim 1 or 2 in which the pulses transmitted by the operator of the remote office are repeated in the common equipment unit on a pulse wire which may be associated in turn with wires. leading to the various electromagnets of the automatic switches. 7. A telephone system as claimed in claim 6 in which the pulse wire may also be associated with a wire terminating in the electromagnet of an auxiliary switch which is put in position by pulses transmitted by the operator of the telephone. remote office in order to determine the type of inrush current to be sent on the called line. 8. A telephone system as claimed in claim 1 or 2 in which the automatic switches include connection circuits and in which the operation of a seeker is not possible on a new call if both pieces of equipment. common are already in use. <Desc / Clms Page number 97> 9. A telephone system as claimed in claim 8 in which the connection circuits are controlled by a distributor whose starting circuit is open if both units of common equipment are in use. 10. A telephone system as claimed in claim 1 or 2 wherein any one of the lines as well as the units of equipment. common by means of which the control is exercised can be put out of service by placing, in determined positions, any of the automatic switches of the remote controlled office. He. A telephone system as claimed in claim 10 in which the lines are brought back into service by placing any of the automatic switches in determined positions different from those which serve to take those lines out of service. 12. A telephone system as claimed in claim 10 wherein if a line and the common equipment associated with it are taken out of service at a time when a call is established on that line the connection is immediately released. . 13. A telephone system as claimed in claim 1 or 2 in which the common equipment unit will associate a line terminating directly at the remote office may be disconnected from that line and connected., -, to the remote office by a bypass path. by bringing any of the automatic switches of the remote controlled office to a determined position. 14. A telephone system as claimed in claim 13 in which the alternative route is established on a trunk circuit in a third office, this trunk circuit being made individual to the common equipment unit. 15. A telephone system as claimed in claim 1 or 3 in which the common equipment unit is released after <Desc / Clms Page number 98> the test of the called line, if it is busy the transmission of the busy tone is initiated by the common equipment unit and continued by the automatic switch. 16. A telephone system as claimed in claim 1 or if the call 2 in which / is to be established in the remotely controlled office, the sending of inrush current to the called line is effected due to the release of the common equipment, if the call is to a remote office l The common equipment is only disconnected when the operator of the remote office answers. 17. A retort telephone system claimed in claim 1 or 2 in which a time device located at the remotely controlled office gives an audible alarm if the operator of the remote office neglects to answer calls within a determined time. 18. A telephone system as claimed in claim 17 in which the local operator can take control of the office when the alarm sounds. 19. A telephone system as claimed in claim 18 in which the local operator can answer 1 .. the call and establish the communication requested and further scheduled so that all calls in which the same common equipment is employed are directed to her. table without interference with the flow of calls through the other common equipment. 20. A telephone system as claimed in claim 18 in which the local operator can perform complete control by taking one of the common equipment units out of service and associating the remaining common equipment unit with its table. allows to establish by means of this one all the communications emitted in the remote controlled office. 21. A telephone system as claimed in claim 1 or 2 wherein the lines connected to prepaid stations are provided with a time device which gives an alarm if the connection to the operator of the remote office is not made within. a specified time and when the connection has been established <Desc / Clms Page number 99> to the attendant to control the transmission of a signal to the remote office to indicate the type of the calling line. 22. A telephone system as claimed in claim 3 wherein the type of inrush current which is to be sent to the trunk line is determined by a rotary switch which is permanently associated with the automatic switch and which is turned on. by an additional train of pulses. 23. A telephone system as claimed in claim 22 in which the rotary switch is provided with a pair of brushes serving to bridge the contacts of the bank to which the wires of the code generator are connected or closing the control circuits for the. application of selective ringing current. 24. A telephone system as claimed in claim 4 wherein when a free line is reached the final selector rotating electromagnet is disconnected from the pulse circuit. 25. A telephone system as claimed in claim 5 wherein each subscriber line is provided with a delayed release relay which remains engaged when the line becomes faulty because the line is returned to calling condition after the release. release the connection. 26. A telephone system in principle as described and shown in the attached plans.