BE412533A - - Google Patents

Description

       

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  Improvements to telephone systems. International Convention: United States Patent Application No. 755,263 filed November 30, 1934 by Thomas Frederick CROCKER of which the applicant is the beneficiary.

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   The present invention relates to telephony systems in general but relates more particularly to telephony systems in which connections are made by means of automatic switches.



   The main object of the invention is to provide suitable apparatus and circuit arrangements for the long distance office of an automatic exchange whereby the automatic selection devices associated with the long distance office are cheaper and at the same time more simulated in operation. .



   The system disclosed here can be considered as an improvement of the automatic toll office described in the patent? 384,791. In this patent the various sections of the trunk switch were specialized to serve a type of traffic such as: 1, traffic entering trunk lines, 2. traffic leaving the local automatic office and which must flow through the trunk junctions leading to other offices and 3. Deferred communications establishment whereby the operator establishes a connection from her position to each of the lines terminating on it, this is known as end-to-end connections.



   According to one of the characteristics of the invention, a trunk switch is provided with trunk circuits each having access to different categories of incoming lines by means of a direct control switch and to different classes of outgoing lines by means of a second indirectly controlled switch, the means being provided to allow the operator to establish connections between incoming lines and outgoing lines of the same category or of different categories by means of the same indirectly controlled switches and the switching circuit junction.

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   According to the invention the incoming lines may be trunk lines coming from a remote office and the connection can be made between these trunk lines and outgoing trunk lines to another office or to local lines. In addition, when the incoming lines are local lines, the connection will be made between these lines and the outgoing trunk lines to a remote office.



   According to another characteristic of the invention, in a trunk switch having trunk circuits, each of the ends of which leads to an automatic switch with indirect control, one of them is operated when the associated trunk circuit is put into service while a direct control switch having access to outgoing lines is temporarily seized and put in position under the control of the operator to mark the desired outgoing line which causes the automatic search for the line marked by the second indirect control switch to complete connection through the indirect control switches and the junction circuit independent of the direct control switch.



   The invention will be better understood from the following description which will be given of it for which reference will be made to the appended drawings which show, for example, a telephone system where the invention is applied.



   Fig. 1 shows the trunk line circuit TLC, particular to the trunk line TC and accessible to the answering switch AS of fig. 3.



   Fig. 2 shows the long distance LD circuit entering from the local selector banks and accessible to the answering switch AS.



   Fig. 3 shows the junction circuit L1 provided with an answer switch AS and a call circuit CS.



   Fig. 4 shows the long distance service circuit

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 TSC which connects the bench of the call switch CS to a serviee selector (not shown) and by means of which communications can be established to the lines of the subscribers of the local automatic office.



   Figs. 5 and 6 show the equipment of the position, it is common to a certain number of junction circuits such as L1 and comprises the handset of the operator and the keys as well as the control relays associated with them.



   Fig. 7 shows the BPS "bypass" selector which has access to all the trunk lines which can be served by the switch. This bypass selector can be considered retort a position equipment since only one selector of this type is provided per operator position.



   Fig. 8 shows a local LC circuit used instead of the TSC circuit of FIG. 4 in the case where the switch described here is used in an office having no automatic long distance but in which use is made of the regular automatic switches for the establishment of communications between the long distance switch and the local lines requested.



   For ease of description, it will be assumed that the switch described is a switch to. two positions including the position equipment shown in fig. 5,6 and 7 is installed in the first position. The identical equipment of the second position is not shown, with the exception of the transfer key K18, fig. 5, interconnected with the transfer key K17 from position 1 to allow any of the operators to use their own handset when they serve both positions during periods of light traffic.



   The cables C1, C2 and 03 of the first position contain the wires necessary for the multiple connections between the common equipment of the position and the different

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 junction circuits, such as the junction circuit L1 of FIG. 3. It will be understood that a sufficient number of trunk circuits must be provided for the flow of the estimated traffic.



   The second position is also provided with a group of junction circuits, all identical to the junction circuit L1 of FIG. 3, and equipment such as that shown in FIGS. 5 and 6 and common to the group of junction circuits.



   The answer switch AS and the call switch CS are rotary switches of the known type having for example 50 pins per bank, only six of them are represented in each switch.



   It will be noted that the first and the second group of the contacts of the bank of the response switch AS are each connected to a remote circuit or to an ordinary trunk circuit such as LD. The third and fourth groups of answering switch bank contacts are allocated to the group of trunk lines of which the TL line is a part, which terminates at a remote automatic office equipped with an identical automatic trunk switch.



   The fifth and sixth groups of answering switch bank contacts are allocated to another group of trunk lines (not shown) and which lead, it is assumed, to a remote manual office, thus having a manual long distance office.



   Contact groups 1 and 2 of the CS call switch banks instead of being assigned to dial-up lines or regular trunk trunks are assigned to trunks leading to the automatic trunk system through which communications are established to local subscribers through trunk service circuits such as TSC.

   The third contact group is assigned to the associated long distance line

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 to the third group of contacts of the AS answer switch bank, the contacts being connected to the trunk circuit TLC through wires 361,362 and 363 of the group of wires 361-365 and 365 'of the call multiple of the trunk line TL . The remainder of the contacts of the comm bank, call switch CS is, identically connected to the call multiple wires of the other trunk lines which appear as calling lines in the bank of the answering switch AS.



   The banks of the different answering switches of the same position are multiplied and an identical, but separate, multiple exists for the banks of the calling switches such as OS. Some of the wires of the multiple bank of the call and answer switches are common to both positions, others are not, for example the contacts of the banks of the identification brush such as 313 of FIG. 3 are not multiplied between the positions since a group of identification lamps such as 331-334 is provided for the other position and the interference between the two positions with regard to the lighting of the lamps is not not desirable.



  In addition, the contacts from 1 to 6 of the banks of the combined supervision and marking brushes such as 314 are not multiple between the positions since the marking wires, such as 109, must be individual at one position.



   In the CS call switch, the multiple bank spans two positions except for the banks of the marking brushes, such as the marking brush 323, which has a separate multiple for each position.



   A detailed description of the operation of the devices will be given below. For this purpose, we will first describe the operations which are carried out for the establishment of an outgoing communication from the office where the automatic long distance equipment is located. It will be admitted that a subscriber, desiring to

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 dialing in with a subscriber at a remote office operated an automatic selector to establish his connection through wires 221, 222 and 223 with an ordinary long distance trunk or a trunk at @ n g. u. e. distance such as that associated with the LD equipment of FIG. 2.



   The relay 202 therefore attracts via the wires 221 and 223 and the left windings of the trans coil. latrice 206 and relay contacts' 201. Relay 202 draws and closes the circuit of relay 203 at its intermediate armature, while at its lower armature it connects the lower talk wire, through contacts of relay 204 and the associated small callback capacitor, to the common wire of the intermittent generator 211. The cadenced ringing tone is therefore transmitted to the subscriber to inform him that the connection has been extended to the trunk switch.



   When relay 203 attracts it marks wire 208 in the banks of the response switches, at both positions, connecting it to the negative, ungrounded pole of the battery through relay 204 and the associated resistor. 205 in parallel; it places a positive on the junction release wire 222 at its lower inner armature and at its bottom armature it places a positive on the starter wire 212 which is common to all circuits such as LD and all circuits such as TLC.



   The wire 212 is moreover common to the two groups of the position equipments and therefore causes an action in both positions. In the first position a circuit closes through the contacts of the relay 516 to attract the relay 517, it attracts and closes the circuit of the answering pilot light 523 to give the operator a visual indication of the call. Relay 507 also closes,: at its upper internal armature, the circuit of the upper winding

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 ery of marginal relay 516 via the eastern contacts of relay 504. This winding / ineffective means that it does not operate the relay but only gives a slight impulse to hasten the attraction of the relay when the current passes through its lower winding.

   Relay 507 also prepares, via wire 341, the circuit by which the answering switch will answer the call, at armature 534 it prepares the test circuit via wire 352. If the position equipment is free in both positions the answer pilot lamps light up in both positions and the two attendants can answer the call.



  The operator in position 1 can answer the call by operating the key K1 in fig. 3 in the conversation position (assuming that the junction L1 is free, as indicated by the fact that the occupancy lamp 336 is off). The keyKl connects the control electronics 310 of the response switch AS to wire 341; it connects relay 301 to wire 342; it opens at one point the blocking circuit of the relay 302 and places an earth on the identification brush 313; it connects the supervision and marking brush 314 to the wire 345; it prepares the blocking circuit of relay 303 by means of wire 344;

   it closes the attraction circuit of relay 303 through the intermediary of wire 343 which is normally grounded through the contacts of relay 502 of the position equipment.



   Relay 303 attracts through wires 343 and locks to its lower inner frame through key K1 contacts and through wire 344, in series with relay 502.



   Relay 502 attracts and disconnects the positive from wire 343 to open the original pull circuit of relay 303 and prevent the pull of a second relay such as relay 303 in the event that Empress operates another key.

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 inadvertent conversation.



   The relay 502 also disconnects the associated talk wires from the primary winding of the translator coil 532 and connects these to the windings of the translator coil 531 so that the circuit is put into the talk position at the same time as one is switched on. opens the circuit of relay 501 at one point.



   In the junction circuit L1, the relay 303 by its operation separates the conversation wires of the junction circuit L1 into two parts; it connects the response section through wires 350 and 357 to the position conversation circuit through contacts of relay 508; it connects the calling end of the junction circuit L1 through the intermediary of the wires 351 and 356 to the position conversation circuit through the armatures 542 and 543 of the relay 517; it combines the test and marking brushes 322 and 323; it connects the blocking circuit of relay 304 to wire 353; it disconnects the control electro 320 from the lower winding of relay 304 as well as the response supervision lamp 337;

   it connects the lower coil of the relay 304 and the lead 355 of the response supervision lamp; it connects the control electro 320 to wire 354.



   The positive placed on wire 535 at the upper middle armature of relay 502 is extended through the contacts of relays 508,505, 506 and of the relay attracted 507 to wire 341 to attract the control electro 310 following a clean control circuit by means of the contacts of the conversation key K1 and the contacts of the non-operated relay 301 to advance the brushes 311-315 step by step in search of the calling circuit.



   The positive is connected to the lower terminal of the test winding of the marginal relay 506 (to the ground wire 535 through contacts of relays 508 and 505) and

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 the other terminal of the test winding is connected through the armature of relay 507 to wire 352, this wire is now connected through contacts of relay 203 to test brush 312 of the response switch.



   The pins encountered by test brush 312 in its rotation are connected either to neutral wires or to grounded wires until the brush 312 encounters a pin associated with a calling circuit, that pin is connected to negative which immediately attracts the relay 506 of the position equipment to remove the positive from the wire 341 and to close the circuit of the relay 504. The removal of the negative from the wire 341 opens the circuit of the control electro 310 so that the brushes 311 to 315 stop on the pin of the circuit calling LD. When the marginal relay 506 attracts it is able to remain attracted without a current flowing in its lower winding because its upper winding is traversed by a current.



   When relay 504 pulls it connects a negative through resistor 536, to wire 342, thereby closing the circuit of relay 301 through the key contacts K1, relay 310 pulls in and closes its own blocking circuit across. the resistor 367 and the control electro 310, it simultaneously disconnects the electro 310 from the wire 341; turns on the occupancy lamp 366 at its lower middle frame; it connects the conversation brushes 311 and 315; and it places a positive directly on the test brush 312 thereby guarding the LD circuit against any intrusion.



   In the circuit at 1 ng a distance LD, the relay 204 which has drawn in parallel with the resistor 205 and in series with the lower winding of the relay 506 remains attracted via the positive given to the wire 208 through the contacts of the relay 301. By attracting relay 204 to its upper armature bypassing the corresponding contacts of the relay

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 203 and disconnects resistor 205 to remove current consumption; it opens the ringing tone circuit at its bottom frame; it prepares a disconnection supervision circuit via wire 209 at its lower inner frame;

   at its lower middle armature it disconnects the positive from the start wire 212, and establishes an additional blocking connection to wire 222, to place the subsequent blocking of the connection established to the LD circuit under the control of the operator and to allow the calling subscriber shaking his fork to call back the operator without there being any danger of cutting off the call.



   Relay 507 in fig. 5 as well as the corresponding relay of the second position release unless another call has been received in the meantime to cause the earthing of wire 212 at another point, in which case both start relays remain engaged for the instant.



   When relay 504 attracts it also opens the circuit of the upper coil of relay 506 which releases as a result of grounding of wire 352 to the upper inner armature of relay 301 and through the contacts of relay 303. The relay 506 does not release immediately however because its lower winding is short-circuited by the positive placed at its two terminals.



   At its highest armature, relay 504 disconnects the operator's headset wires from the conversation wires and connects them to the upper coil of the relay (or buzzer) 503 while at its lower internal armature it closes the own control circuit of the lower winding of relay 503, this works like a buzzer and produces a warning tone in the operator's receiver R which is associated with the secondary winding of the induction coil 531 in the ordinary anti-local circuit.

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   After a short time the relay 506 releases and opens the circuit of the relay 504 which releases and stops the application of the tone on the operator set. In addition, relay 504 applies a positive to the upper terminal of the winding: upper terminal of relay 505 which draws through wire 342 and through the contacts of key K1 in parallel with the winding of relay 301.



   When relay 505 pulls, it disconnects the positive from the lower terminal of the coil of relay 506 and the armature of that relay, it places a negative on wire 346 through contacts of relay 516 and resistor 538.



  The negative on wire 346 turns on the identification lamp 331, assigned to the group of lines or circuits represented by the circuit LD of FIG. 2. This lamp is supplied through the brush 313 and the contacts of the conversation key K1, it identifies the call as coming from a local subscriber.



   The previous description explains the operation when the attendant does not wait for a call to arrive. When not busy, the keyer can hold a key, such as K1, in the talk position, in which case relay 303 of the selected junction circuit and relay 502 of the position equipment are both already engaged. when the call occurs such that the operations described above are carried out without interruption since the relay 507 is attracted.



   After hearing the momentary application of the tone in her receiver, the operator gets in touch with the calling subscriber to obtain the information she needs to continue establishing the call.



   Let us suppose that the caller wishes to obtain a number which one reaches by the long distance line TL of fig, 1. The operator causes the positioning of the brushes of the call switch CS.

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 on the bank contacts associated with a free junction in the group to which the TL line belongs. Because the CS call switch is a simple finder and is not of the direct step-by-step control type, the operator operates the BPS bypass selector in fig. 6 associated with the desired group of trunk lines which causes the successive test by the bypass selector of the trunk lines and the selection of a free line. The CS call switch then searches for a pin marked by the bypass selector and therefore completes the desired connection.



   The BPS bypass selector in fig. 6 is a combined one and two digit selector, normally functioning as a two digit selector. By this arrangement when the number of trunk groups is large and some groups are small a single contact level can be used to serve two or more trunk groups with an unused contact group being left between two adjacent groups in such a way. that the brooms can be brought to these contacts when all the junctions in the previous group are busy and the busy tone can be transmitted to the attendant.



   Of the bank contacts associated with the 631-635 bypass selector brushes the first group of contacts is assumed to be number 1 of the first level while the contacts shown directly above form the first group of second level contacts. It is assumed that the group of trunk lines comprising the line TL of FIG. 1 and reached through the first level of bypass selector bank contacts is a small group containing less than 10 trunk lines, so it shares the first level of bypass selector bank contacts with another group of

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 interurban lines. Since the first trunk line of the group comprising the TL line is connected to the first group of contacts of the first level the digits 1 and 1 are assigned to this group of trunk lines.



   The operation of the bypass selector for selecting a free trunk line and for causing the calling switch CS to connect with the trunk line will be explained below.



   Having received the desired information from the calling subscriber, the operator leaves the key K1 of the junction circuit L1 in the conversation position and operates the key K15 of the position equipment to prepare the circuit of the relays 510 and 509, in series, to his superior contact; this key interposes the pulse contacts 562 of the call device CD on the disconnected branch of the conversation wires associated with the keys K11 to K16; at its lower contacts it closes the circuit of relays 519 and 516 in series.

   The relay 516 attracts and turns off the identification lamp 331 by disconnecting the resistor 538 from the wire of the lamp 346, it disconnects the wire 212 from the relay 507 which releases and turns off the lamp 523 in the event that. relay 507 is still operated if a call is in progress.



   When the relay 519 attracts, to the armature 549 it transfers the wire 354 of the relay 511 and extends it through the contacts of the relays 517 and 518 to the wire 553 of the bypass selector; he lights the lamp 524 at the frame 546; to its inner armature it grounds wire 554 leading to the BPS bypass selector, to supply the upper winding of the marginal relay 518 and prepare a rapid attraction of the relay 518 under the action of its lower winding which is more efficient .



   In the BPS bypass selector, relay 603 attracts via wire 554 through the shaft contacts

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 611 and prepares the circuit of the ascension electro 615 to its lower inner frame; to its upper armature it closes the attraction circuit of relay 604 via blocking wire 554, relay 604 attracts and earths a terminal of the lower winding of relay 601 to its upper inner armature to prepare the attraction of this relay; at its upper armature it opens at certain points the test circuits of relays 606 and 607, at the same time closing its blocking circuit specific to wire 554 through the upper contacts of relay 605.



   As a result of the attraction of relay 519, armature 548 establishes a guard bridge across conversation wires 557 and 558 through delay coil 520 and the upper contacts of relay 510; armatures 545 and 547 connect wires 557 and 558 to wires 551 and 552. So when relay 604 pulls to apply a positive to the lower winding of relay 601, relay 601 pulls through contacts of relay 606 and through. through wires 551 and 552 through delay coil 520. Relay 601 attracts and closes the circuit of relay 602 through contacts; relays 606 and 607. The relay 602 therefore attracts and places a shunt on the upper internal contacts of the relay 604 to keep the relay 601 attracted after the release of the relay 604.

   To its upper armature it connects the test brush 633 to prepare the test circuit of the relay 607; at its lower armature it opens the circuit of the release electro 617 at one point and prepares the ascension electro circuit 615.



   The attendant sends the first digit (1) using her CD call device. When the calling device leaves its normal position the engagement contacts 561 close to prepare the circuit of the relays 510 and 509 in series through the upper contacts of the key K15. Relay

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509 disconnects wires 557 and 558 from the conversation wires of the operator's set and wires 350 and 357 and transfers them to the wires leading to the group of keys containing the key
K15, where these wires are connected to each other through the pulse contacts 562 of the call device CD via the contacts of the key K15.



   Relay 510 at its top armature disconnects delay coil 520 from wires 557 and 558 leaving the relay
601 of the bypass selector drawn under the control of the pulse contacts 562 of the calling device.



   When the calling device is released the pulse contacts 562 momentarily open once and the BPS bypass selector relay 601 releases once momentarily and closes through the contacts of the drawn relays.
602 and 603 the electro-ascension circuit 615 and the lower coil of relay 603 in parallel. The relays
602, 603 and 605 are slow on release while they have a minimal tendency to be slow on pull.



   As a result of the attraction of the ascension electro
615 the. 631-635 brushes are raised one step so that they are opposite the first level of contacts of the associated bench. The shaft contacts 612 prepare the circuit for the release solenoid 617 when the switch shaft leaves its home position, while the shaft contacts
611 opens the initial circuit of relay 603 leaving subsequent operation of this relay depending on the momentary impulses that the lower coil of the relay receives in parallel with the ascending electro 615 during the ascent of the switch.



   .after sending the momentary impulse towards the ascension electro 615, relay 603 releases and opens in a joint the circuit of relay 604 to its upper armature, the relay
604 remains attracted under the action of its blocking circuit which

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 comprises its upper armature and the upper contacts of relay 605. At its lower internal armature, relay 603 transfers the attraction circuit of the ascension electro 615 to the rotation electro 616 via the lower internal contacts of the relays 604 and 605 to prepare the subsequent operation of the electro 616.



   When the call device CD of fig. 3 returns to the rest position the contacts 561 separate to allow the relays 510 and 509 to be released. The relay 510 immediately releases to reestablish the blocking bridge via the delay coil 520 while the relay 509 releases a little later.



   When the attendant transmits the second digit (1) by means of the calling device, the relay 601 releases again momentarily. This time the relay 601, through the lower armature of the operated relay 602, the lower armature of the released relay 603 and the lower armature of the attracted relay 604, momentarily closes the circuit of the rotation electro 616 via of relay 605.

   Relay 605 draws in series with the rotation electro to establish a new circuit for itself and for the rotation electro independent of the lower inner contacts of relay 604; it opens at one point the automatic search circuit for the rotation electro 616 at its lower inner frame; at its upper armature it opens the blocking circuit of relay 604, allowing relay 604 to release and prepare the automatic search circuit of the rotation electro 616. following the operation of the electro 616 under the action of this impulse the brushes 631-635 engage on the first group of contacts of the selected level where the wires 361-365 end.



   At the end of the short time interval following the movement

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 rotation relay 605 releases to start the search operation. In doing so, relay 605 opens, at its lower armature, the control circuit of the rotation electro; to its two upper armatures it applies a positive to the test windings of relays 606 and 607; on its lower internal armature it completes the own control circuit of the rotation electro 616 by means of the contacts of this electro, the lower internal armatures of relays 604 and 605, the contacts of the drawn relay
601 and lightly adjusted contacts of relays 606 and 607.



   Contacts marked "X" close first at the start of armature movement. The automatic search by the BPS bypass selector is then carried out to discover a free line in the selected group. This automatic search continues until one / relay, or both relays
602 and 607 attract when the brushes 633 and 634 encounter a negative.



   If all the lines in the selected groups are occupied, the rotational movement continues until the brushes 631-635 have swept the whole group and they have reached the contacts separating two groups.



   The two contacts separating the groups on which the brushes 634 and 655 are engaged are interconnected so that the attraction circuit of the relay 606 closes by means of the resistor 609, from the lower contacts of the relay 601. , brushes 635 and 634 and relay contacts
607 and 606. When the relay 606 attracts it cuts the own control circuit of the rotation electro 616 at its lower contacts, while at its upper contacts it connects the common wire of the busy tone 636 to the wire 551 and it grounds wire 552 to close the busy tone return circuit thus notifying the attendant that all lines in the group are busy.

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   In the event that the call is intended for the last group of the level, the brushes 631-635 are brought outside the contact bank where they abandon the last line of the group, at this moment the ineffective call contacts 614 are operated, they close the circuit of relay 606 and Empress is informed that all the lines of the group are occupied.



   If the TL trunk line in fig. 1 is free the 633 brush will encounter a negative when the brushes engage on this line after the emission of the second digit 1.



  This negative is extended to wire 363 through resistor 105 and relay 103 in parallel and through the contacts of relay 102. Relay 607 therefore draws into the circuit borrowing the grounded guard wire 564 and the contacts. from relays 605, 604 and 602, it quickly cuts off the automatic search circuit from the rotation electro 616 to the armature 642; at the same frame it places a positive directly on the test brush 633 to mark the trunk line at busy; it closes its blocking circuit by means of its lower winding to its lower inner armature by wire 544 and through the contacts of relays 605 and 604; armatures 643 and 644 it connects the brushes 634 and 635;

   at armature 641 it closes the attraction circuit of the two windings of relay 606 in series.



   The relay 606 attracts and disconnects the wires 551 and 552 from the windings of the relay 601 and extends them through the brushes 631 and 632 of the wires 361 and 362 to the conversation wires of the long distance line TL thus connecting the operator immediately on the interurban line.



   Relay 601 releases because its circuit is cut by relay 606; relay 602 also releases and prepares the circuit of the release electro 617 but this circuit remains open to the armature 642 of the relay 607 and to the contacts

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 of relay 606.



   In the TLC trunk line circuit, the positive placed on wire 363 attracts relay 103 and extends grounded wire 363 to wire 108 which ends at the bank of response switches such as AS, the trunk line. TL will therefore be tested occupied in the banks of the response switches. The relay 103 disconnects the resistor 105 which is located in parallel on its winding, because this resistor is no longer necessary for the duration of the communication; it closes the chain circuit of the group's occupancy lamp at one point; it opens the line relay bridge to its upper frame; to its lower armature it applies a positive to the common point of resistance 104 and relay 102, it will find its use when an incoming call is answered on the TL line to release this relay.



   The operator then calls her colleague from the remote office and during this operation the call switch of the junction circuit L1 functions as a finder to find the line TL.



   When relay 607 of the bypass selector draws wire 553 is grounded to the upper inner contacts of this relay, the positive is therefore connected to wire 354 through the upper armature and the test contact of the relay 518, armature 544 and its idle contact and armature 549 of relay 519. The positive of wire 354 is extended through the contacts of the attracted relay 303 and the lower intermediate armature and the idle contact. from relay 304 to the control electro 320 of the call switch CS through its own control contact.



  The electro therefore functions as a buzzer to drive the brushes 321-325 until the electro circuit is open when the stop relay 518 attracts when the brushes arrive on the contacts assigned to the line TL at the-

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 which BPS bypass selector is now connected.



  The circuit of relay 518 is established as follows: positive at armature 642 of the bypass selector, brush 633 and wire 363, test brush 322 of the call switch, upper intermediate armature and contact at rest of relay 304, attracted relay contacts 303, test brush 323, marking wire 364, bypass selector brush 634, armature 643, wire 555, relay contacts 517, lower winding of marginal relay 518. Relay 518 which is partially energized , attracts quickly when current passes through its lower winding, it disconnects wire 553 from wire 354. Electro 320 of CS call switch ceases to operate and brushes 321-325 remain associated with trunk line TL.



   When relay 518 disconnects wire 553 from wire 354 it extends the latter through the contacts of relay 517 and the coil of relay 304 associated with call switch CS.



  Relays 514 and 304 serially attract in this circuit but the attraction of relay 514 is of no use at this time.



   When relay 304 attracts it closes its blocking circuit to its lower inner armature through resistor 366, it disconnects wire 354 from electro 320 and connects it to supervisory brush 324; it closes an additional circuit for the occupancy lamp 366; it disconnects the test brush 322 from the marking brush 323 and connects it to earth to maintain the guard of the line after the release of the bypass selector; to its upper and lower reinforcements it connects the brushes 321 and 325.



   The connection is therefore established between the remote calling circuit LD, through the junction circuit L1, and the trunk line TL, it comprises the conversation wires of the position equipment of FIG. 5 because the connection relay 303 is attracted.



   As soon as the attendant has sent the line number

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 long distance it operates the call key Kll to alert the calling end of the circuit. The lower group of springs of key K11 sends ringing current to wire 558; the upper interior contacts of the key place the positive on wire 557; the upper contacts apply a positive to the wire associated with relays 510 and 509. Relay 510 attracts to open the control bridge placed on wires 557 and 558 and including delay coil 520, while relay 509 attracts for transferring the wires 557 and 558 to the wires associated with the keys 511 to 516. The inrush current is therefore transmitted to the corresponding wires of the trunk line via the connection established by the BPS bypass selector.



   As soon as the call switch CS has been placed on the TL line as described above, a new path is established for sending the ringing current through the armatures 542 and 543, wires 351 and 356 and the trunk line through contacts of the drawn relay 303 and brushes 321 and 325.



   When the attendant raises her call key Kll, sending of the inrush current ceases and relays 509 and 510 release.



   When the operator of the remote office answers, she puts herself in communication with the operator of the calling office who informs her of the destination of the call, so she can complete the desired connection.



   After having spoken with the operator of the remote office, the operator of the home office releases the bypass selector by raising the send key k15. At the lower contacts of the key opens the circuit of relays 519 and 516 / and these two relays release, relay 516 again allows control of relay 507 by wire 212.



   When relay 519 releases it disconnects wires 557 and 558 from corresponding wires 551 and 552 of the selector

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 bypass as it opens the guard bridge placed on wires 557 and 558 through the delay coil 520. The relay also 519 disconnects / the guard positive of wire 554 which releases the relays 606 and 607 Relay 607 removes the positive from starter wire 553 which releases relay 514 but relay 304 remains attracted through its blocking circuit which contains resistor 366.



   Relays 606 and 607 disconnect the brushes from the bypass selector and close the circuit of the release electro 617 through the armature 642 and its contact at rest, the contacts of the relay 606 and the lower contacts of the relay 601 and 602 and via the shaft contact 612.



  The release electro 617 attracts and restores the bypass selector to the normal position for which the electro circuit is open at the shaft contacts 612.



   Relay 518 releases when its upper winding circuit is opened by removing the positive from wire 554 at the inner contacts of relay 519.



   The attendant keeps her key K1 in the conversation position to block relay 303 until the connection has been extended to the desired line and until the called party has answered or until that she be informed that an immediate response cannot be given to her. In the latter case the operator, in general, asks the calling subscriber to hang up and wait until called back, the communication is established later as a deferred call.



   When the remote subscriber answers, the operator at the home office takes note of the time at the time of the answer in order to be able to calculate the duration of the call later.



   If the operator wishes to get in touch with the calling subscriber while the conversation circuit to the called subscriber remains open, she operates the key K12.

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 which attracts relay 509 which in turn disconnects the two sections of junction circuit L1 from each other and leaves the response section of the junction circuit connected to the operator's station. On the other hand, if the operator wishes to speak to the operator of the remote long distance office or to the called subscriber without the conversation being overheard by the calling subscriber, she operates the key K6 which causes the relay 508 to be attracted to her. turn disconnects the answer section of the junction circuit L1 from the operator's set and leaves the latter connected to the calling section of this circuit.

   The relay 508 releases and again closes the conversation circuit between the two ends of the junction circuit L1 when the key K6 is raised.



   After making sure that the two subscribers are in ltopératrice communication raises the key K1. When this is returned to the rest position, the relay 303 of the junction circuit L1 and the relay 502 of the position equipment release but the relays 301 and 304 remain attracted to maintain the conversation circuit through the junction circuit L1 .

   When the relay 303 releases the conversation circuit only concerns the junction circuit L1 which passes through the contacts of the relay 303 and the temporary connection between the equipment in the operator position of FIG. 5 and the junction circuit Ll is removed
Note that position equipment relay 502 replaces a positive on wire 343 to allow the attendant to operate the junction circuit connection relay (such as relay 303 in any junction circuit) when the conversation key of this junction circuit will be operated.



   In the event that the attendant wishes to monitor the communication to ensure that it continues normally, she lowers the key Kl of the junction circuit Ll in position

 <Desc / Clms Page number 25>

 listening, it therefore connects wires 347 and 348 to the conversation wires of the junction circuit and places a positive on wire 349. Relay 501 attracts and disconnects the receiver R of the operator's set from its normal position in the circuit and associates it with the secondary winding of the attenuated listening transformer 522, which forms an efficient monitoring circuit which allows the operator to place herself in listening on the circuit by deriving the minimum current at vocal frequencies . The monitoring relay 501 releases when the key K1 is restored to the normal position.



   It should be noted that the wires leading to the equipment of the COE chief operator of FIG. 5 are normally connected to the terminals of the normal conversation wires of the operator's set, but they are put in parallel on the receiver R when the supervisory relay 501 is attracted, so that the operator-in-chief can switch on. listening with the operator in position 1 at any time.



   Arrangements have been made to allow the operator to substitute one line for another when she realizes that the connection has been established through a defective trunk line. The substitution can be done when the connection has been established between the two offices and when the operators are in conversation in order to establish communication with the called subscriber, sometimes the poor quality of the transmission on the line may not appear. only when the conversation has already started between the two subscribers. The operator of the home office can control the quality of the transmission between the two subscribers by operating her monitoring key as mentioned above.

   Or the calling subscriber can attract the operator's attention by shaking his fork which causes the supervision lamp 335 to flicker. On the other hand, the operator at the remote office may be the first to notice that the transmission is

 <Desc / Clms Page number 26>

 faulty and it can attract the attention of the operator in the original office by sending the inrush current on the line, which causes the pull of relay 302 and the lighting of the call supervision lamp 335 , the relay 302 is blocked under the control of the blades of the key K1 forming part of the conversation circuit.

   If we admit that the operator of the office of origin discovers herself that the transmission is defective, she will then have to operate her conversation key K1 to cause the re-attraction of relays 502 and 303 and to put in communication with the two subscribers .



  She can then explain to the two subscribers that she is taking care of improving communication conditions and ask them to wait a few moments.



   The operator of the home office then operates the key Kll which attracts relay 509 and transmits the inrush current on the TL trunk line through wires 351 and 356, through contacts of the attracted relay 303 and through the brushes 321 and 325. The sending of the inrush current alerts the operator of the remote office, which enters the current call and gets in touch with the operator of the originating office.



   If it is assumed that the office to which the TL line terminates is an automatic office equipped with a long distance switch such as that described here, each of the operators proceeds in the same way to select another long distance line.



  The operator of the original office operates her K15 key to attract relays 519 and 516. The BPS bypass selector is seized again and placed in the operating position. Now, as previously, the attendant sends the number 11 assigned to the group in question, which causes the bypass selector to select the first free line, the second in the group, for example. By an identical maneuver, the operator of the remote office establishes the connection with the trunk line.

 <Desc / Clms Page number 27>

 since its bypass selector will also select the first free line in the group.



   While keeping the key K15 operated, the attendant then operates the key K14 to cut the connection between the call switch OS of the junction circuit L1 and the trunk line TL. In addition to attracting relays 510 and 509, the K14 key places a positive on wire 353 which bypasses the blocking coil of relay 304 and causes this relay to release, so that the relay is again connected through contacts of the drawn relay 303 to wire 354, now connected through the operated armature 549 of relay 519 to wire 553, grounded in the bypass selector. The CS call switch searches for the line selected by the bypass selector and connects to it.



  Key k14 is reset to re-lock relay 304 when it re-attracts through its lower winding and wire 355 when relay 518 re-attracts to cut off the call switch auto search circuit.



   The line of the called subscriber having been connected to the new line chosen at the remote office, the conversation between the two subscribers can resume and the operator of the original office releases her position equipment by re-establishing the key K15, as well as the key Kl of junction circuit Ll.



   At the end of the conversation, the two subscribers hang up their receivers. When the caller hangs up the relays 202 and 203 of the long distance circuit LD Fig. 2 release but the relay 204 remains attracted through the wire 208, which keeps the junction release wire 222 grounded to block connection at the relevant time. When the relay 202 is released the circuit of the call supervision lamp 335 closes through the relay contacts.

 <Desc / Clms Page number 28>

 202 and 204 and through wire 209, brushes 314 and relay contacts 301. Lamp 335 now shines continuously as for end-of-talk supervision.



   When she receives this signal, the attendant releases the caller's line immediately by releasing the AS answer switch. To do this, the operator lowers the key K1 again to attract the connection relay 303 of the junction circuit L1 and the conversation relay 502 of the position equipment, then the operator lowers the key K8 which attracts the relay 508 and place a positive on wire 342, this wire shunts the winding of relay 301 through contacts of the key K1 of the junction circuit, relay 303 releases and opens the connection between the junction circuit and the calling line . Resistor 367 limits the value of the current flowing in the shunt circuit to prevent unwanted operation of relay 310.



   When relay 301 releases and removes the positive from test brush 312 and therefore wire 208, relay 204 of the LD long distance circuit releases and removes the positive from junction release wire 222 allowing selection devices to enter the calling line. and the LD circuit to release and unblock the subscriber's line.



   Having momentarily lowered his key K8 to release the calling part of the connection, the operator operates his call key Kll to alert the operator of the remote office. In doing so the relay 509 attracts to connect the wires associated with the key KII to the wires 557 and 558, so that the inrush current passes through the called portion of the circuit via the armatures 542 and 543 of the relay 517, wires 351 and 356, contacts of relay 303 and relay 304 and brushes 321 and 325 of call switch CS.

 <Desc / Clms Page number 29>

 



   When the operator of the remote office answers the two operators enter into a conversation and Empress of the remote office is warned that she must cut off the call.



   The attendant at the home office releases the calling portion of the connection by momentarily operating the K14 key which pulls relays 510 and 509 and places a positive on wire 353, thereby closing a shunt for the top winding of the wire. relay 304 which releases and disconnects the called portion of the connection. Resistor 366 prevents a harmful increase in current when the shunt establishes.



   The attendant puts the key K1 back to rest, which releases relay 303 and relay 502.



   If the attendant receives a call on a long distance LD line and cannot establish the communication immediately, she can ask the calling subscriber to stay on the line or she can ask him to hang up by informing him that it will call it back when the link is established. If we assume that the calling subscriber hangs up and that the link has been extended to the called subscriber who answered the operator asks the called party to wait a moment. to call back the calling subscriber, it operates the key K4 which causes the relay 508 to attract, the latter associating the wires 350 and 351 with the key; it connects the calling circuit to wire 357; it connects a negative to wire 350.

   Assuming that trunk circuit L1 is the one used, it is seen that wires 350 and 357 are connected through switch AS to long distance circuit LD which is connected to the calling line. Therefore the relay 201 attracts under the action of the polarity placed on the wire 221 and opens the bridge comprising the right windings of the translator coil; it transfers the incoming wire 221 to ground to provide a return path for the inrush current; he trans-

 <Desc / Clms Page number 30>

 feeds the incoming wire 223 to the wire 210, thereby allowing the recall current to pass from the wire 210 to the wire 223 and from there to the called line. when the key K4 is reset, sending of the inrush current ceases and relays 508 and 201 release.



   When the calling subscriber answers the relay 202, which had released when the subscriber hung up and which had turned on the lamp 335, re-attracts and turns off the lamp.



   The conversation can be established.



   It should be noted in passing that the key K5 is used when the operator wishes to ring on a trunk line connected to the answer switch of a trunk circuit.



   Suppose now that an operator of a remote office establishes a call to a local subscriber of the office represented, by means of the long distance line TL. It will therefore momentarily send the inrush current on the TL line.



   In the circuit of the trunk line TLC, the relay 101 (placed at the terminals of the wires of the trunk junction TL through the contacts of the relay 102 and through the associated capacitors) follows the variations of the inrush alternating current and makes its pulses beat. contacts, it follows that the shunt normally existing at the terminals of the winding of relay 102 opens.

   When this shunt is open, relay 102 draws in series with resistor 104 and at another point opens the shunt circuit at its lower armature; it disconnects the wire 363 from the winding of the relay 103 and connects it to the earth at its upper armature to mark the line at Unoccupied in the banks of the bypass selectors; it marks the TL line as being on call by placing a negative on wire 108 through relay 103 and resistor 104 in parallel;

   to its lower frame it puts

 <Desc / Clms Page number 31>

 the starter wire 212 to ground to alert an operator by means of the response pilot light such as the light 523 of FIG. 5 or to automatically start a response switch such as the paging AS switch. from the calling line if an operator has a lowered conversation key in a free trunk and ready to answer the call which therefore leads directly to the operator's set.



   Suppose the trunk circuit L1 is the one that has been selected at the first position to serve the next call and the answering switch AS connects to the terminals of the trunk line TL before an answering switch AS of the second position could have done so. Under these conditions, the relay 506 of the position equipment attracts to stop the search movement, its circuit takes the following path: wire 362, contacts of relay 303, test brush 313, wire 103, contacts of the drawn relay 102, resistor 105 and relay 103 in parallel.

   Pulling of relay 506 causes a momentary pull of relay 504 to give the operator an audible indication and to place a negative on wire 342 through resistor 536 to pull relay 302 through contact contacts. the key Kl. Relay 301 turns on busy lamp 336 and connects the AS response switch brushes.



   In the TLC trunk line circuit relay 103 attracts to open the line bridge, it locks to wire 108 and disconnects resistor 105, it bypasses relay 102 which releases and removes the positive from starter wire 212.



   When, from her conversation with the operator of the remote office, the operator of the home office realizes that a call must be established with a subscriber

 <Desc / Clms Page number 32>

 from this office it causes the association of the call switch CS of the junction circuit L1 and a free service interurban circuit, such as the TSC service interurban circuit of FIG. 4 by means of which communication can be completed. To do this, the operator lowers the key K16. In addition to activating the CD call device the key K16 at its upper contacts causes relays 515 and 516 to be drawn in series.



   At its lower armature, relay 516 puts a positive through the lower winding of relay 513 to wire 358 which is multiple at all the contacts of the banks of the marking brushes of the call switches, such as brush 323, and which are associated with long distance service junctions. Relay 515 also closes at its upper inner frame and through contacts of relay 514, the circuit of the upper coil of relay 513, which energizes and prepares to attract quickly when the circuit laid out through its lower coil and wire 358 will close. A branch circuit, in parallel with the upper winding of relay 513, draws relays 510 and 509 in series.

   Relay 509 in addition to transferring wires 557 and 558 to branch wires ending in keys, extends the positive of wire 535 (grounded to contacts of operated talk relay 502) through contacts of attracted relay 515 and from the contacts of the non-attracted relays 513 and 514 and through the armature 549 to the wire 354. The presence of a positive on the wire 354 at this moment, closes the circuit of the electro to own control 320 through contacts of the attracted relay 303 and contacts of the relay 304. The relay 510 disconnects wire 354 from wire 355 (normally interconnected by supervisory relay 511).



   The Electro 320 works like a buzzer

 <Desc / Clms Page number 33>

 to move the brushes 321-325 until they reach the contacts of a free long distance service junction, namely the TSC junction of fig. 4. When this junction is gripped brushes 322 find a negative on wire 372, it is led through resistor 405 of the TSC trunk service circuit. This negative is extended through the brush 323 (connected to the brush 322 through contacts of the relay 303) to the wire 358. The relay 513 therefore attracts through the wire 358. And removes, at its upper armature , the positive of wire 453 thereby allowing the operation of the electro 320 of the CS call switch and leaving the brushes 321-325 engaged on the pins of the bank to which the wires 371-374 are connected.



   Relay 513 also attracts relay 512 to its upper inner frame, relay 512 extends the positive through wire 355 and through the contacts of relay 303 to relay 304 which attracts and connects the associated brushes, it locks in position attracted to its upper interior contacts through resistor 366.



   Relay 513 also closes the circuit of the upper coil of relay 514, which includes contacts of the drawn relays 515,509 and 502. By pulling the relay 514 locks to the armature 541 through the contacts of the relay 515; at armature 540 it opens at an additional point the circuit through which the positive was applied to wire 354; at its upper internal contacts it opens the circuit of the upper winding of relay 513 and the circuit of relays 510 and 509. Relays 510 and 509 release as well as relay 513 because its circuit borrowing wire 358 has been opened at the contacts of the relay 304. Relay 512 is released by the action of relay 513.



   At its upper frame, relay 514 closes the cir-

 <Desc / Clms Page number 34>

 of the lamp 524 to inform the operator that she can send the digits of the requested number by means of the calling device CD.



   When supervisory broom 324 is connected to the contacts of relay 304, the circuit of relay 401 of the TSC trunk service circuit closes through wire 373. This circuit includes contacts of the drawn relay 303, wire 354, 1. armature 549 and its contact at rest, contacts of relays 510, 511 and resistor 537. Relay 511 does not draw in this circuit in series with the high resistance of the upper winding of relay 401. Lamp 337 does not therefore not light up.



   In the TSC long distance service circuit, when relay 401 attracts through wire 373, it opens the bypass connections of the windings of the translator coil 402 and bridges the left windings of the translator coil on the incoming conversation wires. 371 and 374 and bridges the right windings of the translator coil on the outgoing wires 406 and 408. The line relay (not shown} of the long distance selector to which the wires 406-408 terminate now draws through the wires 406 and 408 in series with the lower winding of the electrically polarized relay 403 to prepare the long distance selector for operation.The polarizing winding of the relay 403 is fed by wire 372 through the contacts of the drawn relay 401 and resistor 409.

   The current therefore flows through the lower winding of the supervision relay 403 in a direction such as it assumes the effect of the polarizing winding of the relay. The relay 403 therefore does not attract. When the attendant uses the call device and it leaves the rest position, relays 510 and 509 attract; in series by means of the key K16 and con-

 <Desc / Clms Page number 35>

 nect wires 557 and 558 to pulse contacts 562 of the calling device, they disconnect the negative (applied through resistor 537 and relay 511) from wire 354, thereby opening the circuit of relay 401 of the TSC interurban service circuit of fig. 4.



   Relay 401 bypasses the windings of the translator coil 402 and opens the front and rear bridges of the TSC circuit so that the incoming wire 371 is extended to the 408 wire and the incoming wire 374 is extended to the outgoing wire 406 .



   The trunk line relay (not shown) of the trunk service selector to which wires 406 and 408 terminate is kept attracted by wires 371-374, brushes 321 and 325, relay contacts 303, wires 351 and 356, armatures 542 and 543, wires 557 and 558, pickup relay contacts 509, K16 key contacts, and CD calling device pulse contacts 562. It should be noted that this transfer takes place without interrupting the continuity of the circuit leading to the line relay of the long distance service selector because the relay 509 attracts first to prepare the circuit while the relay 401 of the long distance service circuit transfers the relay. line from the blocking bridge (through relay 403) to incoming wires 371 and 374 through closing contacts before breaking.



   When the call device CD of fig. 5 returns to the normal position, it interrupts the control circuit a certain number of times which depends on the value of the digit to be transmitted.



   When the calling device reaches the rest position, the relays 510 and 509 successively release. Relay 510 again places a negative, through resistor 537 and the coil of relay 511, on wire 354 which causes relay 401 to reopen as previously described.

 <Desc / Clms Page number 36>

 



   The same operations are repeated each time the calling device is activated for sending one of the following digits of the requested number.



   When the last digit has been sent and the connection to the called line has been established and in the event that the called line is free, the direction of the current is reversed in the wires 406 and 408 coming out of the long distance service selector, therefore. makes the electrically biased relay 403 attract and remove the shunt from the winding of the relay 404. The relay 404 now attracts and shunts the lower low resistance winding of the 401 relay to the high resistance upper winding of the same relay, so the current increases. in wire 373 and in relay 511 which attracts and causes relay 512 to attract.

   Relay 512 places a positive on wire 355 which turns on supervisory lamp 337, through contacts of relay 303, to indicate that the called line is free and that the connection has been established.



   The attendant can then speak with the attendant at the home office and know if she is ready or not, to place the called subscriber's call.



   To make the call, the operator lowers the key K11 which sends the ringing current to the conversation wires and causes the relays 510 and 509 to be drawn through the contacts of the non-operated key K15. Relay 510 opens the supervision circuit and the control bridge to its upper inner frame, which releases relay 401 of the TSC long distance service circuit and relay 511 of the position equipment. Relay 511 releases relay 512 to turn off supervisory lamp 337 and relay 401 releases TSC circuit to allow inrush current to flow.



   Following the sending of the ringing current the called subscriber is ringed.



   When the key K11 is raised, the relays 509 and 510

 <Desc / Clms Page number 37>

 release and relays 511, 512 and 401 re-attract and lamp 337 re-ignites.



   When the called subscriber answers the calling circuit is cut and the inrush current ceases to flow through the wires exiting the TSC junction circuit. At this moment the relay 401 releases as well as the relay 511 which releases the relay 512 and finally the lamp 337 goes out to give the response supervision.



   The operator then straightens the key K1, which releases the relay 303 which releases the position equipment, which can then be used in conjunction with: one of the other junction circuits.



   When the connection relay is released, voice frequency currents can flow directly through junction circuit L1 without passing through the position equipment.



  In addition, the response supervision lamp 337 is connected directly to the brush 324 through the contacts of the attracted relay 304 and the contacts of the released relay 303. At this point the lamp 337 is lit or not depending on whether the relay 404 is attracted or no since the lamp does not glow when in series with the upper coil of relay 401.



   In order to explain how the operator can interchange the long distance lines when she notices that the one in service is defective for the conversation, it will be assumed that the operator of the remote office while monitoring the communication discovers that the transmission is bad. Under these conditions, the operator of the remote office sends the inrush current on the TL line to attract the relay 302 of the function circuit L1, the latter blocks on itself through the contacts of the key K1, in at the same time as it closes the power supply circuit of the call supervision lamp 335.



   When the attendant lowers the key K1 to the

 <Desc / Clms Page number 38>

 conversation to attract the relay 303 and the relay 502 of the position equipment, the relay 302 releases and the call supervision lamp 335 goes out. The operator of the remote office then warns her colleague of the faulty state of the TL trunk line and asks her to establish a connection by means of another trunk line of the same group so that communication can be established by this other line.

   To do this, the attendant proceeds in an almost identical manner to that which was previously described for placing the BPS bypass selector in position on the first free line of the group comprising the TL line and to cause the reset. position of the AS answering switch on the new trunk line. Since she wishes to put the response switch AS back in position, the attendant operates the key K13 which, in addition to the connections made by the key K15, closes the circuit for attracting the relay 517 and 516 in series.



  Relays 516, 517 and 519 attract and relay 519 grabs the BPS bypass selector and holds it ready to operate. Relay 517 at its lower armature prepares a new circuit for feeding wire 342 through resistor 539; it disconnects the test coil of relay 518 from wire 555 and connects it to wire 556 to mark a wire in the answer switch bank instead of the call switch bank CS; at the armature 544 it transfers the wire 553 to the wire 341; at its upper inner frame it disconnects wire 355 which will therefore not be earthed when relay 518 draws; he disconnects the wires 351 and 356 at the frames 542 and 543 to isolate the called station, at this moment;

   at its upper frame it places the wire 345 to the ground to allow the closing of the marking circuit by means of the brush 314 of the call switch AS.



   It will be noted that the positive is removed from the upper pair of contacts of keys Kll and K5 so that neither key K5 nor key K11 can attract the relays associated with them 508 or 509 and the operator cannot hand - @

 <Desc / Clms Page number 39>

 holding ringing neither one of the other ends of his positional equipment.



   When the attendant transmits the two-digit number assigned to the group of long distance lines including the TL line by means of her CD calling device, the BPS bypass selector operates as described above to perform a search in the group. Let us suppose that the second line in the group is free and that it is entered by the operation of relays 606 and 607 of the bypass selector. The wire corresponding to wire 363 and associated with the second trunk line is earthed, and the relay corresponding to relay 103 of the TLC circuit of FIG. 1 is attracted.



   The operator momentarily operates the key K8 which attracts the relay 508 which disconnects the response end of the junction circuit Ll from the operator's station for the moment and which places a positive on the wire 342 which causes the closing of a shunt circuit on the winding of relay 301, through the contacts of key K1, relay 301 releases and opens its blocking circuit to its upper armature. The relay 301 being released and the starting wire of the bypass selector BPS 553 being earthed (to the contacts of the relay 607) and connected to the wire 341 to the armature 544 of the drawn relay 517 the own control electro 310 of the response switch AS operates through the contacts of the key K1 to drive the brushes 311-315 until the control circuit is opened by the action of the relay 518.

   Relay 518 attracts when the trunk line selected by the BPS bypass selector is reached.



   Wire 345 is grounded in the position equipment at the top contacts of relay 517. Ground wire 345 is connected through contacts of key K1 to brush 314. Now when the response switch brushes AS will reach the fourth contact group of the

 <Desc / Clms Page number 40>

 bench shown, they will be connected to the second line of the group including the TL trunk line. The grounded broom 314 extends the positive on the marker wire of the second trunk line (corresponding to TL line 109 wire) which connects to a marker wire (same as 365 wire) and terminates at the bench of the bypass selector. Sweeper 635 is now on the bank contact to which the marker wire of the second trunk line (corresponding to wire 365 of the trunk line TL) is connected.

   The positive is therefore extended through the brush 635, the armature 644, the wire 556 and the lower armature of the attracted relay 517 to the winding of the relay 518. The relay 518 attracts and opens the circuit. described above for the operation of the electro 310 of the response switch AS to its upper frame, leaving the brushes of the response switch associated with the second trunk line of the group comprising the TL line.



   The pull of the relay 518 connects a positive to the wire 342 through the resistor 539, it closes the circuit of the relay 301 through the contacts of the key K1, the relay 301 attracts and connects the associated brushes, moreover it locks on itself to its upper armature through resistor 367 and the control electro 310.



   It will in fact be understood that the operator is in a telephone connection with the newly selected trunk line as soon as the trunk line has been entered by the BPS bypass selector and that a second conversation circuit to the trunk line is completed to the attendant set by means of the brushes of the AS response switch when this switch is placed on the new trunk line as described above.

   The attendant is warned of the final position of the control switch.

 <Desc / Clms Page number 41>

 response AS and the attraction of relay 301 when call supervision lamp 335 lights up through the contacts of relay 301 due to the presence of the positive given by wire 345 to brush 314 as indicated previously.



   The attendant returns the K13 key to rest, which releases relays 519, 517 and 516 as well as the bypass selector. When relay 516 releases, the negative is connected to wire 346 through resistor 538 and the contacts of the drawn relay 505, this causes the identification lamp 333 associated with the second row of the group in question to light up through the brush 313 and contacts of the operated key Kl. The attendant can therefore locate the group line that was used to re-establish the connection. It should be noted that the upper winding of relay 505 is fed through wire 342 in parallel with the winding of relay 301 of junction circuit L1.



   Following the release of the relay 517 the wires 351 and 356 are again connected to the armatures 542 and 543 to the position conversation circuit so that the two subscribers can put themselves in conversation even if the conversation key K1 is operated. , or at least the called subscriber can be informed by the operator that he can resume the interrupted conversation.



   An identical substitution having been made by the operator of the remote office and in principle in the same way the two subscribers can enter into conversation on the new long distance line. The conversation circuit only comprises the direct passage through the junction circuit L1 as soon as the operator straightens the key K1 and allows the release of the relay 303.



   It should in fact be understood that the junction lines such as TL are connected in the same order in the banks of the bypass selectors of the two offices in such a way

 <Desc / Clms Page number 42>

 that these selectors select the same free trunk line under the conditions described above. When the called subscriber hangs up, the direction of the current is once again reversed in the wires 406 and 408 leaving the TSC long distance service circuit, so relay 404 again attracts and places the lower winding of relay 401 in shunt on the upper winding to increase in-. Core the value of the current in wire 373 and cause the response supervision lamp 337 to light up.



   At about the same time inrush current is received on the trunk line from the remote office to attract relay 302 and turn on call supervision lamp 335.



   The attendant then lowers the key to the talk position to speak with the operator at the remote office, who informs her that the connection may be broken. To cut the connection, the operator momentarily operates the key K7 which puts wire 342 to the ground to bypass relay 301 and places a positive on wire 353 to bypass the blocking circuit of relay 304. As a result, these two relays release, each of them opens its blocking circuit and disconnects the associated brushes. The operator then returns the key K1 to the rest position, which releases the relay 303 and returns the junction circuit L1 to the normal position. when relay 304 releases and disconnects supervisory broom 324, the circuit of relay 401 of the TSC trunk service circuit opens.

   The relay 401 therefore releases and again connects the incoming wires 371 and 374 to the outgoing wires 408 and 406 while simultaneously opening the two bridges. Since there is no bridge on wires 371 and 374 at this time the connection through the toll select train to the called line is released in the well known manner.

 <Desc / Clms Page number 43>

 



   How to establish a transit communication will be explained above. By communication in transit is meant a call received on a line of a group which must be extended to a line of another group, an office equipped as shown here being a connection point.



   Assume that a call is received on a trunk line of the second group and the trunk circuit L1 answer switch AS is seized and connects to the calling trunk line.



   It is assumed that the calling operator informs the called operator that the call should be transmitted on a trunk line group containing the TL line in fig.l.



  The attendant called lowers her K15 key to prepare the BPS bypass selector to operate. This operates under the action of the impulses emitted by the calling device to send the number 11 by bringing its brushes in front of the first level of the contact bank and rotating them on the contacts assigned to the trunk group. longed for. It is assumed that the TL line is the one that has been selected, in this case the connection is established to it by the bypass selector and the call switch CS connects to the trunk line as described above. above, and the relay 304 of the junction circuit L1 attracts.



   The intermediary operator then lowers her call key Kll to notify the operator of the office where the long distance line TL ends.



   As soon as the operator of the remote office answers, the intermediate operator raises the key K1 of the junction circuit L1 and lets the operators of the originating and terminating offices talk to each other, who regulate the final establishment of the desired connection, it no longer takes care of communication at all except when relay 302 calls it

 <Desc / Clms Page number 44>

 asks to intervene.



   When the passing connection must be released, one or the other of the operators at the ends of the link sends the ringing current on the line, the relay 302 locks on itself under the control of the key E1 and turns on the supervision lamp 335.



   The attendant noticing that the supervision lamp 335 is burning lowers the key K1 to attract the relay 303 and put herself in communication with that of the operators which is connected to the established communication. If asked, the intermediate operator can lower her call key to alert the other operator, this operation is usually only necessary in the case where the trunk lines are of such length that the inrush current is attenuated on a line. of sufficient quantity so that it does not pass on the other line with sufficient intensity to attract the end relay or any other signal in the third office.



   To release the connection in transit, the attendant momentarily lowers the key K7 which bypasses the relays 301 and 304 which release, then the attendant raises the key K1 and the connection is released.



   How to proceed for a deferred call will be described below. The calling subscriber is informed that he must hang up and wait for the callback. The connection which was initially established between the calling line and the trunk switch is therefore cut. For convenience it can be assumed that the call is intended for a subscriber who can be reached via the TL trunk line.



     'When the attendant is ready to establish the connection, she takes a free junction circuit, the junction circuit L1, and prevents the reply switch of the junction circuit from being seized by an incoming call by lowering a

 <Desc / Clms Page number 45>

 keys K16, K15 and K13 since in each case the relay 516 attracts through one of the relays 515, 517 and 519. Let us suppose that the key K16 is the one which has been operated since the operator usually wishes to call the local subscriber first, to make sure it is still ready, before putting the trunk line into service to set up the deferred call.



   When the key K16 is operated to associate the calling device with the conversation circuit, the relays 515 and 513 attract. Relay 516 prevents the positive action of starter wire 212 on relay 507 and relay 515 at its upper contacts extends positive to wire 354 to start call switch CS, while armature lower it places a positive, through the lower coil of the relay 515, on the wire 358 to stop the call switch CS on a free long distance service circuit, such as the TSC long distance service circuit.



   After the TSC long distance service circuit has been entered the operator transmits through the calling device and establishes a connection through the TSC circuit to the called line. She rings the called party using the Kll key and asks him to wait while she manages to complete the connection.



   The operator then lowers the key K13 and releases the key K16 which releases the relay 515, but the relay 516 remains drawn in series with the relays 517 and 519, these two relays being operated through the contacts of the key K13 for '' prepare the bypass selector and the AS response switch which must find the position taken by the BPS bypass selector.



   The bypass selector operates under the action of pulses and then automatically searches for a line

 <Desc / Clms Page number 46>

 free in the group of interurban lines, i.e. the TL line
The positive now extends to wire 341 to operate the AS response switch control electro 310 through key K1 contacts instead of electro 320 as before. The AS response switch operates until it connects to the selected line TL, at this time relay 518 attracts to cut the circuit of the control electro and to close the circuit of wire 343 which attracts relay 301.

   The circuit for relay 518 at this time includes wire 345, grounded to the top contacts of relay 517, brush 314, wires 109 and 365, brush 635 from the bypass selector, wire 556 and contacts of the relay attracted 517.



   The connection between the calling line and the TL trunk line has now been completed through the trunk circuit L1.



   The operator can then lower the key K5 to warn the operator of the office where the TL line is overflowing and to request his help to establish deferred communication.



   The established connection is released as described above.



   It will be understood that it is preferable to use an interurban selection train for the establishment of the communications to the local subscribers while the communications between the subscribers of the same office are established by so-called "local" selection trains. In some cases, however, long distance operators can use the regular selection train to establish connections to called subscribers.



   If the long distance switch is installed in an office where long distance calls are to be completed by

 <Desc / Clms Page number 47>

 the intermediary of the local selection train to the called subscribers, the interurban service circuit TSC of FIG. 1 is replaced by the local LC circuit of fig. 7 ..



   When the local LC circuit is seized by 'the CS switch for example the test circuit of the previous switch in wire 372' includes contacts from relay 701 and resistor 705. Relay 701 draws through supervisory wire 373 and through the high resistance of the top winding to open the direct connection between the incoming and outgoing conversation wires and to bridge the left and right windings of the translator spool 702 to the incoming and outgoing wires, respectively. The line relay (not shown) of the local selector to which the wires 406 'and 408' terminate attracts through the right windings of the translator coil, the upper winding of the electrically polarized relay 703 and the resistor 704.

   The polarizing winding of relay 703 is powered by a circuit comprising the junction release wire 372 ', contacts of relay 701 and resistor 709. As indicated by the direction of the arrows associated with the windings of supervisory relay 703 the current flowing through one winding has the same action as flowing through the other winding so that the relay now attracts to shunt the low resistance lower winding of relay 701 across the high resistance upper winding which turns on the supervisory lamp 337 of the call switch CS.



   The attendant then sends the requested number using her calling device. Whenever the current in the incoming supervision wire 373 'is interrupted the relay 701 releases to disconnect the windings of the translator coil 702 and to establish a direct path, it connects the incoming wires 371' and 374 'directly to the outgoing wires 406t and

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 408 'to allow the pulse to pass directly through the LC circuit.



   Each time the calling device returns to its normal position, the current is restored in the supervision wire 373 'and the relay 701 re-attracts, which causes the electrically polarized relay 703 to re-attract.



   After the connection has been established to the requested line and the called party answers the current in the wires 406 'and 408' is reversed which releases the polarized relay 705, this disconnects the lower winding of the relay 701 , therefore reducing the value of the current in the wire 373 'to turn off the response supervision lamp 337 of the junction circuit L1.



   Other interesting features of the BPS bypass selector will now be explained.



   When the group of trunk lines includes 8 or 10 lines and the traffic that they carry is therefore relatively high, a single number can be used advantageously to call this group of lines, which saves the time necessary to send a second digit. . It is assumed that the second level of the bypass selector contact bank is reserved for a large single group and it is therefore certain that this group is the desired group when the brushes of the bypass selector are brought in front of the second level of the switches. bench contacts. The contacts of the second level 613 are provided to close when the brushes are brought in front of the second level.



   It should be remembered that the relays 602 and 604 are continuously attracted while the relay 601 vibrates its contacts to operate the ascension electro 615 which controls the vertical movement of the bypass selector, and that the relay 615 releases at the end of the ascension movement,

 <Desc / Clms Page number 49>

 but the relay 604 remains attracted by a blocking circuit which includes the grounded blocking wire 554 and contacts of the relay 605 as well as its own upper armature.



  So when the brushes 631-635 are placed in front of the second level of the bank contacts and the relay 603 releases the automatic control circuit of the rotation electro 616 closes via the relay 605 at the lower contacts of the relay 603, this circuit includes the shaft contacts 613 and the lower contacts of the draw relay 604.



   Electro 616 draws along this circuit to drive brushes 631-635 on the first group of contacts of the second level bench and relay 605 draws in order to cut off at its upper armature the blocking circuit described above and now relay 604, from such that it releases to trigger the regular automatic search by the selector.



   In order to ensure that the relay 604 is kept attracted in this case for a time long enough to allow the rotation electro 616 to complete its step by having the circuit closing of the rotation electro 616 cause the closing of a new blocking circuit of relay 604 in parallel with the rotation electro and through the switch contacts of the rotation electro.



  This circuit comprises the operated lower inner armature of relay 604, resistor 608, and operated upper armature of relay 604. This auxiliary blocking circuit remains closed until the rotation electro 616 has been operated in a proper manner. sufficient to separate its contacts, at this time the brushes 631 will have engaged on the first group of contacts of the selected level. The presence of resistor 608 reduces the current to a very low value in the second blocking circuit and the relay 604 quickly releases when

 <Desc / Clms Page number 50>

   The opening of the electrical switch contacts 516 is produced.

   By releasing the relay 604 opens at its lower contact the circuit of the rotation electro 616 which releases and again closes its switch contacts, but the relay 604 does not re-attract because it has opened its blocking circuit.



  Resistor 608 prevents premature pulling of electro 616 in parallel with the initial blocking circuit of relay 604.



   A little later, relay 605 releases and triggers the regular search movement by the selector.



   If it is desired that the operator can connect to a specifically determined line of the group of trunk lines connected to the second level of contacts, the trunk lines of this group can be multiplied in another level of the selector for this purpose. It will in fact be understood that at each level, except on the second, the attendant can operate the bypass selector to bring the brushes to any line of the group, instead of bringing the brushes to rest on the first line of 'a group, at the end of sending the second digit assigned to it. This feature is applicable if the attendant works in conjunction with an attendant of a remote manual office and if it is necessary to substitute a good line for a defective incoming line in the group.

   To make this substitution, the attendant asks the operator of the remote manual office for the number of the new long distance line that she wishes to use instead of the defective line, using the BPS bypass selector she establishes the connection with the line. good determined by the operator of the remote manual office.



   If it is desired to use a long distance office such as that described here for a separate service one or more positions can be designated to establish the calls requested by local subscribers, one or more positions

 <Desc / Clms Page number 51>

 can be reserved for setting up incoming calls from long distance lines, and one or more positions can be used for routing deferred calls.

   With this arrangement, long distance service trunks can be removed from call switch banks of trunk circuits at positions which only serve calls from local subscribers, and trunks from local selector banks to long distance circuits. (such as the LD circuit in fig. 2) can be omitted from the answering switches of the trunk circuits at the positions reserved for the establishment of inbound calls on the trunk lines, while the positions which carry deferred calls only can be equipped in the same way.
 EMI51.1



    

Claims (1)

CLAIMS. 1. A telephone system comprising a long distance office provided with trunk circuits each having access to incoming lines of different categories through an answering switch and to different categories of outgoing lines through '' a call switch, each of which is provided with control equipment by means of which the operator can establish connections between the incoming and outgoing lines of any category through a circuit of any junction. 2. A telephone system comprising a long distance office provided with trunk circuits, each of them leading to automatic switches having access to incoming and outgoing lines respectively, in which upon an incoming call an automatic switch is put into service for connect to the calling line, the connection being completed by the operator by means of a second switch either to a long distance line if the incoming call comes from the local office or to an outgoing local line or a long distance line outgoing if the incoming call is from a remote office. 3. A telephone system comprising a long distance office provided with trunk circuits, each of them leading to automatic switches having access to incoming and outgoing lines respectively, in which each trunk circuit is provided with a key whose use by the operator causes the automatic search for a free line by an automatic switch, the connection being completed by the operator by means of a second switch either to a local line or to an interurban line, depending on the operation of the line. 'another key. @ <Desc / Clms Page number 53> 4. A telephone system comprising a long-distance office provided with trunk circuits, each of them leading to automatic switches having access to incoming and outgoing lines respectively, in which upon an incoming call an automatic switch is put into service for connect to the calling line while the second automatic switch operates under the operator's control either to connect to a circuit leading to the line of a local subscriber or to operate the search for a long distance line determined. 5. A telephone system comprising a long distance office with trunk circuits each end of which is terminated by a direct / direct switch in which one of the direct / direct switches operates when the trunk circuit to which it is associated is put into service, while a direct control switch, having access to groups of outgoing trunk lines, is temporarily associated with the trunk circuit and is in position, under the control of the operator, on the desired group of outgoing lines, it extends a marking circuit to the second indirectly controlled switch to cause the latter to select a line in the desired group, the connection being established through the indirectly controlled switches and the junction circuit independent of the direct controlled switch. 6. A telephone system comprising a long distance office provided with junction circuits each leading to an indirectly controlled switch having access respectively to incoming lines and to long distance lines in which during an outgoing call the operator causes the connection of the junction circuit to the calling circuit <Desc / Clms Page number 54> through one of the indirectly controlled switches and operates a direct controlled switch temporarily associated with the junction circuit and having access to outgoing lines to set the switch to the desired group in which it selects and marks a line free from the group, therefore a second indirectly controlled switch associated with the junction circuit automatically searches for the marked line to complete the connection through the junction circuit. A retort telephone system as claimed in claims 1, 2, 3 or 4 in which lamps are provided at each operator position for the purpose of identifying the group to which the incoming calling line belongs. A telephone system as claimed in claim 8 in which a group of lamps is associated with each trunk circuit through contacts of the bank of an indirectly controlled switch on the incoming side. A telephone system as claimed in claim 1, Z, 3, 4, 5,6 or 8 in which the banks of the indirect control switch on the incoming side are multiplied with the banks of the corresponding indirect control switches of the other positions except of the bench associated with the identification lamps which is individual to each position. A telephone system as claimed in claim 1, a or 4 in which each trunk circuit is provided with a key which when operated by the operator enables an incoming circuit to be automatically associated with the trunk circuit by the through one of the indirectly controlled switches. <Desc / Clms Page number 55> A telephone system as claimed in claim 3 or 4 wherein depending on whether the operator operates one key or the other of a group of two keys the second. indirectly controlled switch searches for either a free line or a marked line. A telephone system as claimed in claim 11 in which the free line is determined by a negative and the line marked by a positive. A telephone system as claimed in claim 11 in which the marking, extended to one bank of the second indirectly operated switch, comes from a direct operated switch which is placed under the control of the operator. operator according to the group to which the desired line belongs. A telephone system as claimed in claim 5 in which the directly controlled switch subsequently performs the automatic search for a free line in the group and in which the second indirectly controlled switch performs the automatic search for that line. A telephone system as claimed in claim 1, 2, 3, 4, 5 or 6 in which means are provided which, when the connection has been established, allow the operator to release the connection either from the line. incoming line, either from the outgoing line, or from both in order to change the line on which the connection is established. A telephone system as claimed in claim 15 in which a directly operated switch is entered by the operation of an individual key to each attendant, the return of the key to the normal position when the indirectly operated switch is turned on. <Desc / Clms Page number 56> in position on the line used to reset the direct-operated switch to rest. A telephone system as claimed in claim 15 wherein if it is desired to change either the incoming trunk line or the outgoing line, the direct operated switch is operated to select the free line in the group, thereby the second switch to. indirect command is released and operated again to find the selected row. A telephone system as claimed in claim 15 in which as soon as the directly operated switch is turned on the inrush current is transmitted over the outgoing line through contacts of that switch while when the second indirectly operated switch is found. on the outgoing line marked the inrush current is transmitted on this line through the junction circuit and the second indirectly controlled switch. A telephone system as claimed in claim 17 wherein when the direct operated switch is reopened to select another free line a corresponding operation is performed in the remote office to select the next free line in the group. A telephone system as claimed in claim 1, 2, 3, 4, 5 or 6 in which on a delayed call the operator first establishes the connection of the outgoing end via the first switch. - indirectly controlled switch and if the line is free complete the connection to the incoming line via the second indirectly controlled switch. A telephone system in principle as described and shown in the attached plans.