BE416389A - - Google Patents

Description

       

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  Improvements to telephone systems.

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   The present invention relates to telephony systems in general, but more particularly relates to small systems of the type commonly known as private automatic switches.



   It is the rule that private automatic switches are the property of individuals or corporate organizations and that they are installed in factories or establishments to which they provide telephone service from a certain number of local stations and where they are used for monitoring. - establish connections with the junction lines to one or more offices of the public telephone network.



   The main object of the invention is to provide an advanced private automatic telephone system of the type described in patent No. 383519.



   One of the characteristics of the invention lies in the fact that it has provided trunk circuits comprising a finder and a connector, to select and transfer calls coming from the public network to the lines of local subscribers, even if all the local trunk circuits are occupied.



   Another feature resides in the fact that one has provided a trunk distributor used by two groups of trunks for incoming and outgoing calls by these two groups.



   Another feature resides in the fact that a device has been provided to allow split calling for the incoming connectors and for the local connectors which ensures the correct selection of any of the two subscribers connected to the called line.



   Another feature of the invention relates to the improved routing switch in which the terminating switch makes it possible to put a call on hold on a busy line and to offer an incoming call to a busy line.

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 called busy.



   Other characteristics of the invention relate more particularly to improvements to the circuits, they will become more tangible by the detailed description of the appended drawings which include FIGS. 1 to 10 inclusive, which represent, by means of ordinary schematic circuits, the apparatus necessary for the understanding of the invention.



   To the left of fig. 1 shows a local subscriber set S provided with a push button PB by means of which the subscriber can take and receive communications with the public network, transfer calls, and block the line to the public network when taking or receiving local communications. The local researcher represented to the right of fig. 1 is a two movement switch which performs a vertical movement to find the group in which the calling line is located and a rotational movement to find the particular calling line in the selected group. The local oheroheur has access to local subscriber lines and to. one or more lines terminating at the passage switch.

   The lines of the local subscribers and the line to the transit switch are multiplied, as shown, in the banks of the trunks finders, inbound connectors and local connectors. In the lower left corner of fig. 1 we can see the group tagging and starting circuits of the local researchers.



   Fig. 2 represents the local connector which constitutes one end of the junction circuit, it is a two-movement switch which operates directly under the control of the pulses to find the called line.



  The lower right corner is reserved for a line comprising two grouped subscriber sets S2 and S3. Subscriber lines

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 The premises terminate in the first nine levels, while the tenth level is used for the establishment of outgoing communications, inbound communications and communications to the gateway switch.



   Fig. 3 shows a local distributor which pre-selects free trunk circuits and causes the local pager to operate when a subscriber makes a call.



   Fig. 4 represents one of the junctin seekers, from the points of view of construction and operation, he is identical to the local searcher, he has access to the lines of local subscribers and to one or more lines leading to the transit switch.



   Fig. 5 shows the two-way junction particular to the junction finder shown in FIG. 4. Each junction finder and each junction line have a branch which ends in the arrival searchers' benches, one of which is shown in fig. 7.



   Fig. 6 schematically represents the distributor of junctions used with the two groups of junctions which were discussed above.



   Fig. 7 represents one of the arrival searchers and the relays associated with it, while fig: 8 shows the input connector and the relays associated with it.



   Inbound trunk circuits are used during the transfer of communications with the public network or are used by local subscribers to make a local call while they keep the link to the public office blocked.



   In the left part of fig. 9 there is shown a transfer distributor and an inlet distributor in the right part. The transfer distributor is used when communication with the public network is

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 transferred from one local line to another; the incoming distributor is used to designate the free incoming junction circuit that will be put into service.



   Fig. 9à shows the way in which the different sheets of the plans must be assembled.



   All local lines such as S, S1, S2 and S3 are provided with normal automatic telephones.



  Full-service subscribers can take and receive communications with the publia network, they have a push-button station, such as PB, mounted on the base of this station or on the associated bell.



  Partial service subscribers can answer calls coming from the public network but cannot make such calls their station is provided with an identical push button but these lines are connected to the negative through a resistor, such as Z, by the intermediary of an individual wire, - at the corresponding contact of the bench accessible to the researcher's brush 174. Restricted service subscribers have sets which are not provided with a push-button, they can only take and receive local calls.



   The changeover switch shown in fig. 10 comprises a CD call device, a mobile telephone handset HS comprising a microphone and a receiver, springs MS which close when the handset HS is lifted, an induction coil 10 and a ringer RB. The various keys, which will be discussed later, are mounted near the passage switch. The relay 1020 is common to all the release keys, such as the PK key, and to all the response keys, such as the AK key, while the other relays included in FIG. 10 are individual one-position relays including wires 1092 through 1096 inclusive.



  The other release and response keys (which are not shown) each have a similar group of relays and identical wires that terminate in the banks of the

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 switches. Buzzer B is used when the attendant answers calls from the public network, while trunk calls are used when any of the subscribers to. full service can answer these calls. There are as many common call signals on the trunks, distributed throughout the establishment, as necessary to allow subscribers to determine when a call from the public network is pending.



   A detailed description of the operation will be given below.



   For the study of a local call, it will be assumed that subscriber s (fig. 1) wishes to get in touch with subscriber S2 (fig. 2). When it picks up, the springs of the fork HS close the attraction circuit of relay 103 as follows: positive, upper winding of relay 103, armature 105, wire 102, lower winding of induction coil IC, microphone T, springs of 'call device pulses, upper fork springs, wire lol, armature 104 :, middle and lower windings of relay 103, negative. As a result of the resistance of one of these windings, the relay 103 attracts only at the first stroke and closes its armatures 106 and 108.

   To armature 106, relay 103 connects through wire 147 the negative of its lower winding to the contact of bank 142 to mark the line of station S as the calling line; to the armature 108 it connects the positive to the N 1 contacts of the vertical bench and closes the circuit which borrows the resistance and the wire 109 and passes through the winding of the relay 310 of the local junction circuit distributor.



   The relay 310 by drawing, to the armature 311 prepares the circuit of the relay 120, to the armature 312 it closes the circuit of the relay 320 in the event that the brushes of the distributor are

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 engaged on the bank contacts to which a free jonotion circuit is connected. The attraction circuit of relay 320 borrows the positive of wire 397, the armatures 375, 366, 344, 312, the relay 320, the switch springs and the coil of the control electro-magnet 333 and ends in the negative . If the distributor brushes are engaged on a busy jumper circuit, wire 396 is grounded such that relay 320 is shorted through brush 386, armature 325, and its top terminal.

   The positive is extended through the switching springs and the coil of the electro-control magnet 333 which causes the stepping of the distributor brushes until they have selected a control circuit. free junction, the relay 320 alone attracts in the circuit described above.



  At armature 327, relay 320 closes its own blocking circuit, at armature 329 it establishes the circuit of relay 360 which draws into the following circuit: positive at armature 329, armature 373, upper winding of relay 360 , negative.



  At armature 361, relay 360 closes the circuit of the ascent electromagnet 150, at armature 362 it establishes the circuit of relay 120, at armature 364 it closes the circuit of relay at time 350, at the armature 366 opens the initial attraction circuit of the relay 320. As a result, the relay 350 attracts and the vibrating armature 351 operates and closes its upper contacts. At armature 351, relay 350 closes the blocking circuit through the lower winding of relay 360 by means of armatures 365, 328 and 351, it also closes the attraction circuit of time start relay 370 to through the normally closed contacts of the armature 374.

   At armature 372, relay 370 opens the circuit of relay 350, at armature 373 it opens the circuit passing through the upper coil of the relay

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 360 and at armature 374 it closes its blocking circuit through armature 329. Relay 350 releases which causes armature 351 to vibrate between its upper and lower contacts for a determined time, as a result of the presence of the block. ballast 352. The relay 360 therefore remains attracted for a certain time by the vibration of the armature 351.



   The attraction of the relay 320 causes the attraction of the relay 120 through the wire 391 and the brush 381. When the armature 121 is in contact at rest, one of the earth links is disconnected from the wire 397, when the contact is on. wire 193 is grounded. At armature 122 wire 194 is grounded, it closes the circuit of the lower coil of relay 110, at armature 123 ground wire 396 is connected to cam springs 170.



   On contact 323 the relay 320 closes the circuit of the ascent electromagnet 150 through the wire 395 and the brush 385, the electromagnet attracts and on contact 151 closes the circuit of the relay 330 which attracts and opens the circuit of the electromagnet 150 at contact 331, this electromagnet releases and releases the relay 330, each attraction of the electromagnet 150 raises the shaft and the brushes of the local researcher and the interaction between the electromagnet 150 and relay 330 continues until vertical test brush 176 encounters a grounded bank contact, relay 340 then draws in series with relay 330 through brush 383, wire 393 and vertical broom 176. Relay 330 remains drawn into this circuit to keep the lift solenoid 150 control circuit open.

   Relay 340 opens its blocking circuit to armature 342, to armature '341 it opens its initial attraction circuit and places test lead 393 to earth, to armature 343 it transfers the control circuit - drive from the ascent electromagnet 150 to the rotation electromagnet 140. When in contact at rest, the armature 341 opens /

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 the circuit of the relay 330 which releases, to the armature 331 it closes the circuit of attraction of the electro rotation magnet 140 including the positive taken to the armature 361., the wire 394, the winding of the electro of rotation 140, the negative. The brushes of the local researcher therefore rotate and at the armature 141 the wire 392 is grounded, this attracts the relay 330 which at the armature 331 interrupts the circuit of the electro-magnet of rotation 140.

   This interaction between the rotating electro-magnet and the relay 330 continues until the brush 173 meets the marked contact to which the calling line ends, the relay 110 then attracts into the circuit comprising: 'a positive taken from the armature 321, brush 383, wire 393, brush 173, idle contact 142, lower winding of relay 103, negative. The relay 110 attracts and at the armatures 111 and 112 puts the relay 210 on; at the armature 114 it puts the brush 173 to the ground to allow the relay 103 to draw in the second time and to mark the calling line as occupied, at the armature 115 it opens the circuit of the electro magnet of rotation 140 and prepare a circuit to wire 396.



   Relay 210 now attracts, at armature 211 it closes the circuit of relay 250 and relay 260 through the engagement springs 214 of the connector.



  At armature 252, relay 250 puts wire 193 to earth to keep the called line busy, at armature 253 it places another earth on blocking wire 194. The relay
260 pulling to frame 261 connects the invitation tone to be transmitted to the lower conversation wire.



   When the relay 103 draws in the second time it is disconnected from the wires of the calling line to the frames 104 and 105, at the frame 107 the positive is disconnected from the vertical bench? 1 and wire 109, therefore relay 310 releases

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 if no other subscriber is currently on a call, at armature 311 it opens the circuit of relay 120 which releases after a certain time. At armature 123, relay 120 earths wire 396 through searcher engagement springs 162 and the control electromagnet circuit 333 closes through starter 325 and of its contact at work, of the winding of the electromagnet and of the negative. The electro magnet remains attracted and its switching springs opens the circuit of relay 320 which releases.

   On contact with the working of the armature 325, the relay 330 opens the circuit of the control electromagnet 333, with the contact at rest it closes the own control circuit of the electromagnet 333, this one operates as a buzzer and step by step the local distributor until brush 386 is no longer engaged on a contact which results in a grounded ground wire.



  At armature 328, relay 320 opens the circuit of the lower winding of relay 360 which releases, at armature 329 it opens the blocking circuit of relay 390 which releases before relay 360. At armature 365 relay 360 opens the blocking circuit of relay 340 which releases.



   If, however, relay 310 remains attracted after opening contact 108, because starter wire 109 is grounded for another call, starter 115 pulling of relay 110 closes the circuit. the control electro 333 when the relay 330 releases. With its switching springs, the electro-magnet control 333 opens the cooked air of the relay 320 which releases, on contact at rest of the armature 325 it establishes the own control circuit of the electro-magnet 333 to cause the selection. , by the distributor, of a free local trunk circuit which will serve the pending call.

   Likewise, if the local researcher /

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 does not find the calling line, the shaft and brushes rotate to the eleventh position where the cam springs 170 close and ground the guard wire 396 to cause the distributor to search for another circuit of free jonotion.



   If, as a result of any fault, the transfer relay 340 does not attract, the time release device kicks in after a period determined to cause the distributor to search for another local trunk circuit. . Relay 360 is kept drawn in the circuit of its lower winding for a determined time as a result of the vibrations of armature 351, after a certain time relay 360 releases shortly after armature 351 has failed to switch on. contact with its upper and lower frames.

   At armature 361 the circuit of the electromagnet of ascent 150 opens, at armature 362 the circuit of the searcher start relay 120 is cut, the circuit of the control electromagnet 333 closes at the armature 363. The attraction of the electro-magnet control 333 opens with the switching springs the circuit of the relay 320 which releases, the release of this relay has the same effects as those already described, at the armature 326 it opens the circuit of the control electro magnet 333 to cause the advancement of one step of the distributor brushes, at this point the distributor operates according to its pre-selection circuit to search for another free junction circuit.

   In the local finder the relay 120 releases and at its armature 123 puts the ground wire 396 to keep the local junction circuit occupied until it has completely returned to idle, at armature 121 it closes the circuit of the electro-magnet release 120 via the engagement springs 161 and

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 the armature 113. The operation of the electromagnet of release 130 causes the return to the normal position of the shaft and the seeker brushes, consequently the searcher engagement springs, 161 and 162, return to rest and open the circuit of the electromagnet release 130 and remove the earth from the ground wire 396.



   Returning to the normal operation of the local junction circuit, it will be remembered that the invitation tone to be transmitted having been sent to the calling subscriber, the latter can start sending the digits 9 and 1 to call the set. S2. The line relay thereby releases nine times and on each release transmits a pulse to the ascending electromagnet 218 as follows: positive at armature 211 and its idle contact, armature 254 and its contact at rest. work, armature 263 and its contact at work, armature 276 and its contact at rest, winding of the ascent electromagnet 218, negative.

   The ascent electromagnet 218 moves the shaft and connector brushes up one step with each pulse until the brushes stop at the ninth level. - Engagement springs 181 are actuated at the first step in ascension, they put the ground wire 396, the engagement springs 214 are actuated and open the initial attraction circuit of the ascension series relay 216 which, as a result of its delay on release remains attracted by the action of the current pulse flowing through its lower winding. shortly after relay 260 release and at armature 261 disconnects the call tone to transmit from the calling line, at armature 263 it transfers the pulse circuit from the ascent electromagnet 218 to the electro rotation magnet 219.



   The second digit 1 is then emitted, the relay 210 still follows the pulses and at the armature 211 closes

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 the rotation electromagnet attraction circuit 219 as follows; positive to armature 211 and its contact at rest, armature 254 and its contact at work, armature 263 and its contact at rest, armature 223, winding of the rotation series relay 290, armature 209, winding of the electro magnet of rotation 218, negative. The connector brushes therefore rotate one step and engage on the first contact of the ninth level .a uq u el ends the line of station S2. The rotation series relay 290 attracts in series with the rotation electromagnet 219 and as a result of its release delay maintains its armatures attracted throughout the rotational movement.

   At armature 291 relay 290 closes the circuit of relay 220 and at armature 292 it bypasses armature 223 to keep the pulse circuit closed if relay 220 were to attract while sending pulses.



   If the called line is busy wire 269 is grounded and relay 220 draws in the following circuit: positive to wire 269 through bank contact 266, brush 226, armature 291 and on contact, armature 205 , upper winding of relay 220, negative. In frame 223 the relay 220 opens at one point the circuit of the electro-magnet of rotation, on contact to work it prepares its own blocking circuit and to the armature 221 it connects the busy tone to the wire. lower conversationalist to transmit this indication to the calling subscriber.

   When relay 290 releases after sending the pulses, the blocking circuit of relay 220 is established as follows: positive at armature 251, armature 222 and its contact on, normally closed springs controlled by armature 291, armature 295, upper winding of relay 220, negative. The release of the connection when the calling subscriber hangs up will be canceled later.



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If the called line is free, relay 220 does not pull and when relay 290 releases a little after the sending of the pulses, the circuit of relay 200 closes in series with the lower winding of the line and cut-off relay. of the called line, as follows: positive to armature 251, armature 222 and its contact at rest, lower winding of relay 200, contact at rest and armature 291, brush 266, wire 269, lower winding of the line relay and of cut of the called line, negative. The line and break relay attracts in this circuit, it disconnects from the wires of the called line and opens the circuit of the common starting wire 109, it finally marks the called line as busy line in the bench of local researchers.

   The relay 200 first closes its blocking circuit specific to the 2077 armature and therefore it draws completely, at the reinforcements 201, 202 and 204 it completes the inrush current sending circuit, at the armature 203 it closes. the call return circuit through the capacitor RBCL, at the armature 209 it opens the circuit of the rotary magnet 219.



   When the called subscriber answers, the relay circuit 230 closes in the circuit for sending the call current.



  Relay 230 closes its own blocking circuit for armature 232 and completely attracts the remainder of its armatutes.



  At reinforcements 231 and 233, relay 230 opens the inrush current deflection circuit and establishes the conversation circuit which borrows the wires marked in solid reinforced lines.



  Relay 220 draws into the called subscriber's loop circuit via a positive taken from armature 253. The called subscriber supply current is supplied through the relay windings. 220, that of the calling subscriber is brought through the windings of relay 210.



   At the end of the conversation when the called subscriber

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 hangs up relay 220 releases. When the calling subscriber hangs up relay 210 releases and at armature 211 opens the circuit of relay 250 which releases, at armature 251 this relay disconnects the earth of wire 193 to release relay 103 and to release the calling line , at armature 253 it removes the positive of wire 194 to release relays 110, 230 and 200, finally at armature 254 it completes the circuit of the electro-magnet of release 217 through the intermediary of the frame 211 and of the engagement springs 215 of the connector.

   The relay 110 releases and the armature 113 closes the circuit of the electro-magnet release 130 of the local finder by means of the engagement springs 161 of the finder and armature 121. The relays 230 and 200 release, the latter to the armature 206 disconnects the earth of the wire 269 to release the called line and to release the line and cut relay which is associated with it.



  Seeker engagement springs 161 again ground the common occupant wire 297, and connector engagement contacts 181 disconnect ground from ground wire 396 to indicate that this local trunk circuit is available for all. subsequent call.



   It will now be assumed that the subscriber S calls the subscriber S3. The ringtone of the set S3 being connected to the negative line wire 267 the calling subscriber must first transmit the digit 1 and then the line number, or 91, in order to operate the ringing of the set S3. The finder and distributor work in the same way as before and when the subscriber S issues the number 1, the connector shaft raises its brushes to the first level. In this case the shaft springs 213 are actuated and when the ascension series relay 260 releases shortly after the sending of the pulse, the attraction circuit of the relay 270 closes to the armature 262 through its lower winding.

   Relay 270 at-

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 pulls and at armature 274 establishes its own blocking circuit by means of guard wire 194, at armatures 271 and 272 it reverses the connections to the call generator, at armature 273 it opens the circuit of the call generator. invitation tone to be transmitted, to armature 275 it completes the attraction circuit of relay 260 and finally to armature 276 it transfers the pulse circuit of the ascent electromagnet to relay 280 The relay 260 to the armature 262 opens the initial attraction circuit of the relay 270 which is blocked to the wire. blocking 194, at armature 263 it prepares the circuit for receiving the pulses of relay 280.



   Subscriber S then sends the next digit, 9.



  Relay 210 follows the pulses to attract relay 280 under the action of the first pulse only, and the ascending electromagnet under the action of the other pulses of the second digit. Under the action of the first pulse, the relay 210 closes the attraction circuit of the relay 280 at the first time, as follows: positive via the armature 211 and its contact at rest, armature 254 and its contact at work, armature 263 and its contact at work, armature 276 and its contact at work, armature 283 and its contact at rest, lower winding of relay 280, negative. Relay 280 attracts and closes its armature 281 only, in doing so it short-circuits its top winding through the earth taken at ground wire 194.

   When the line relay 210 draws at the end of the first pulse the short circuit of the upper winding of the relay 280 is removed and this relay draws at the second time. At armature 282, relay 280 opens the circuit of relay 260 but the latter, due to its release delay, remains attracted during the sending of the pulses, at armature 283 and its contact at rest it opens the circuit

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   initial attraction of relay 280, on contact with work it prepares the circuit of the electro-magnet of ascent 218.



  The remaining eight pulses of the second digit are now transmitted to the ascension electro magnet so that the connector brushes are brought to the ninth level.



   Operation from this point is the same as described previously except that the current from the call generator is passed on the negative line wire.



  The ringing tone transmitted to the calling subscriber uses the conversation wires marked with reinforced lines and the RBC capacitors.



   The cam springs 212 are actuated in a tenth rotational step, they are provided to allow subscribers to connect to a call by code switch and to pulse to that switch to transmit the code which will operate the callers. special signals distributed throughout the establishment.

   The pulse circuit according to which the code switch is actuated borrows: armature 211 and its contact at rest, armature 254 and its contact at work, armature 263 and its contact at rest, the contact at work and the cam springs 212, the armature 373 and its contact at rest, the contact at rest and the armature 233, the armature 204, the brush 225 and then the bano contacts which come from the code switch and terminate in the local counselor benches.



   Assume now that an incoming call is received on wires 507 and 508. Inrush current from the public office attracts relay 504 which at armature 505 closes the circuit of call relay 500. armature 501 relay 500 closes the attraction circuit of relay 1007 in fig. 10 if the SK key is in the normal position, at the armature

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 502 it closes the circuit of the relay in time 509 and at the armature 503 it completes the circuit of the relay 580. At the armature 1008 the relay 1007 earths the common wire which extends to all the signals. trunk calls that are placed at various locations throughout the facility to attract the attention of local subscribers when there is a need to answer a pending incoming call.

   Relay 580 attracts in the following circuit: positive at armature 444 and its contact at rest, armature 466 and its contact at rest, wire 529, armature 503, lower winding of relay 580 and negative, it locks at l armature 582 and vibrating armature 591.



  At armature 583 relay 580 completes the attraction circuit of relay 570, at armature 581 and when it contacts rest it removes the earth of wire 532 to mark this junction as a calling junction in the junction distributor bench, when in contact with the armature 581, it puts the wire 533 to the ground to make the common relay 630 attract. The relay 630 by attracting, to the armature 631 and its contact at rest disconnects the ground of wire 636 to allow the local subscriber to answer the incoming call.



   Any subscriber with full service can answer the incoming call by sending an answer number, in this case 0 and 3. When a full service subscriber goes off hook and sends digits 0 and 3 for answer the incoming call, the finder and the local connector operate as before and when the 290-series relay releases after sending the pulses, the switching relay 200 draws in series with the 667 and 668 relays. This circuit is the following: positive through armature 251, armature 222 and its contact at rest, lower winding of relay 200, contact at rest and armature 291, brush 226, bank contact 255, wire 636, armature 631 and contact open, winding of marginal relay 667, lower and upper windings of relay 668, negative.

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  The relay 667 being marginal does not attract in series with the two windings of the relay 668. The relay 200 by attracting is blocked at the armature 207, at the armature 206 it puts the wire 636 to the ground to mark the occupation. from this position in the other connectors.



   In the junction distributor the relay 668 attracts in the circuit described above, at armature 690 it disconnects the negative from the rest of the chain control relays, at armature 691 it locks on itself through its lower winding and causes the attraction of the marginal relay 667 unless the distributor is already in service for other calls, in which case one of the armatures 675,681 or 684 can be in the actuated position, if the distributor of junctions n is not in service, the marginal relay 667 attracts.

   At armature 685, relay 687 completes the test circuit which will allow the junction distributor to find the junction on which the incoming call has ended, at armature 686 it closes the attraction circuit of relay 640, to armature 687 it grounds wire 646 to mark the calling line in the junction finder bench through the local junction circuit, at armature 688 it grounds wire 647 to mark the group in which is the line which answers, finally to the reinforcement 689 it puts the wire 1098 to the ground, this one intervenes only when it is the operator who answers the incoming calls.



   If the brush 617 is engaged on a grounded contact, the relay 640 is interrupted and the control electromagnet 619 operates in its own control circuit comprising: a grounded wire, such as wire 532 which extends to the free junction, the brush 617, the winding of the relay 640 which is therefore short-circuited
As soon as the broom 617 engages on a bench contact

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 which is not earthed or on a contact corresponding to the junction where the incoming call has just been completed, the short circuit of relay 640 is removed and relay 640 draws in series with the control electromagnet 619 by through the earth taken at armature 686. The control electromagnet 619 is marginal, it does not attract in series with the high resistance of the winding of the relay 640.

   At armature 641, relay 640 earths wire 479, corresponding to the connection in question, to attract start relay 450, at armature 643 it attracts relay 650 and at armature 642 it opens its initial attraction circuit and the circuit of the rotation electromagnet 619 but due to the presence of the resistor R which bridges the armature 622 the relay 640 remains attracted.



  Relay 450 attracting, at armature 452 closes the circuit of the energizing winding of relay 470, at armature 454 it completes the circuit of the ascent electromagnet 416 and at armature 455 it closes its blocking circuit to wire 479 grounded.



   The ascent electromagnet 416 attracts and at its contacts 419 closes the attraction circuit of relay 420, At the first step of ascent of the brushes, the engagement springs 469 open the initial attraction circuit of relay 450 which remains in the operated position by means of its armature 465. The relay 420 and the lift electromagnet 415 cooperate in an identical manner to that which has been described for the relay 330 and the electromagnet 150 until until vertical broom 438 has found the vertical bank contact marked positive when relay 667 has pulled, thereby relay 410 draws in series with relay 420 when earth is removed at armature 419 by releasing the electromagnet I ascend 416.



   The relay 410 attraction and blocking circuit, the

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 of relay 420 is: positive to armature 688, wire 647, bank contact 257 of local connector, local connector brush 288, wire 196, searcher brush 175, bank contact 145, wire 155 and in the present case through the first vertical bench N 1, vertical brush 428, armature 414, lower winding of relay 410, winding of relay 420, negative. At armature 413, relay 410 closes its blocking circuit, the initial attraction circuit being opened shortly after contact 414 so that relay 420 releases.

   At the armature 421 the relay 420 closes the circuit of the rotation electromagnet 415 and the electromagnet and the relay 420 cooperate as it has already been said to rotate the brushes of the jonotion finder until the relay 470 attracts in series with relay 240 of the local connection circuit and in the following circuit:

   wire positive 687, wire 646, normally open contact 256, brush 227, armature 208, transfer relay lower winding 240, lead 195, brush 174, contact idle 143, lead 153, seeker bench contact 475, brush 425, rest contact and armature 441, armature 451 and upper winding of relay 470, negative, Relay 470 to armature 471 completes the attraction circuit of relay 530 through the intermediary from the aontact at rest of the armature 404, to the armature 472 and its contact at rest it opens the control circuit of the control electromagnet, at the contact at work it establishes the magnet circuit of the relay 460 by the 'intermediate of the positive taken from the frame 454,

   at armature 473 it completes the blocking circuit of relay 460 and finally at armature 469 it removes the short-circuit of the upper winding of relay 580 to make it rapid on release. Relay 460 attracting to armatures 461 and 462 connects conversation wires 102 and 101 to both windings of relay 510 and to positive and negative through the windings

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 lower and upper relay 550, respectively. At armature 463 relay 460 grounds wire 100 to keep relay 103 engaged and to maintain occupancy of the responding line.

   With armature 466 and its contact at rest, relay 460 opens the blocking circuit of release relay 580, on contact with armature 466 on contact it connects the earth of armature 444 to the windings. excitation of relay 470 to keep it attracted. Relay 550 draws into the loop circuit of the responding subscriber through the coil of relay 510, but the latter being a differential relay does not draw into this circuit. Relay 550 at armature 552 completes the circuit of relay 560, at armature 551 it bridges the right-hand bearing of the translating coil on wires 507 and 508 of the junction to cause the attraction of the current cutout relay call to the public office and suppress the sending of this current on wires 507 and 508.

   Relay 560 by attracting, at armature 561 keeps relay 570 attracted, at armature 562 it disconnects relay 504, working under alternating current, from the two junction wires 507 and 508. Relay 504 releases and at armature 505 opens the circuit of relay 500 which releases after a short time.



  Relay 580 releases when its blocking circuit is opened by relay 460, at armature 581 and its contact at work it disconnects the earth of wire 533 to cause the release of relay 630 provided that no other incoming call is made. pending, at armature 581 and its contact at rest, it grounds wire 532 to short-air relay 640 of the release junction distributor.



  Relay 500 releases a little after its circuit has been opened definitively at armature 505, at armature 501 it opens the circuit of relay 1007 which releases and turns off the various call signals on junctions distributed in the field. - establishment. At armature 502, relay 500 opens the circuit

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 of the time relay 590 which releases its armature 591, this one vibrates for a certain time: This has no effect at the moment because the junction finder has already connected to the local line which responds.



   In the distributor, relay 630 releases if no other call has arrived in the meantime, at armature 631 it opens the circuit of relays 667 and 668 to its working contact, when the contact is idle it puts wires 636 and 1097 To the earth. If a second incoming call had occurred, relays 630 would have been kept drawn and relays 667 and 668 would have released when the local connector releases and removes ground from wire 636 as will be described below.



  Relay 640 releases when it is short-circuited, at armature 641 it opens the starter relay 450 circuit which releases. At armature 643 and its contact on, the relay 640 opens the circuit of the release relay 650 which releases after a certain time, when the contact is at rest it completes the holding circuit in the action position. electro magnet of rotation 619 during the release time of the release relay 650. When the relay 650 releases, the own control circuit of the electromagnet which closes at contact 642 becomes operative if another call occurs.



  Relay 667 by slackening in armature 685 opens the own control circuit of the electromagnet just as it eliminates the short-circuit of relay 640, in armature 686 it opens the circuit of starting relay 620 for ensure the release of it. At armature 687 the relay 667 disconnects the earth of wire 646 to remove the researcher marker polarity in the connector banks, at armature 688 it also removes the positive marking of wire 647, at armature 689 it removes the earth from wire 1098. Relay 668 when releasing, to armatures 690 and 691 reconnects the negative to allow the attraction of any of the relays

  <Desc / Clms Page number 24>

 control chain of FIG. 6.

   When the delayed release relay 650 releases, at armature 651 it opens the circuit of the control electromagnet 619 to cause the distributor brushes to advance by one step. The trunk distributor is now in the normal position and can be used for subsequent calls.



   If we come back to the study of the functioning of the functional air-cooker, we see that the relay 240 has drawn in series with the relay 470, at armature 243 it closes its own blocking circuit, at armatures 241 and 242 it. opens the air-cooked of relay-210 which releases and at armature 211 it opens the circuit of relay 250. Relay 250 by releasing at armature 252 disconnects the earth of brush 173 and wire 147 which however remains set. earth via wire 100. At armature 253 it opens the blocking circuit of relays 110, 220, 270, 280, 230 and 200 which release, finally at armature 254 it completes the relay circuit. the release electromagnet 217. The brushes of the local connector are therefore returned to the normal position.

   Releasing switching relay 200 to armature 206, or recalling the switch brushes, disconnects ground from wire 636 to cause relays 667 and 668 to release if they have not yet released by this time. The relay 110, by releasing the armature 113, completes the circuit of the electro-magnet releasing the searcher 130, thereby the electromagnet returns the searcher brushes to the normal position.



   In the junction finder, relay 450 releases when its circuit is open as a result of releasing relay 640 which disconnects ground from wire 479 to armature 641. At armature 451 relay 450 opens. the initial attraction circuit of relay 470, at armature 452 it cuts one of the earth connections of the lower bias winding of relay 470, at armature 454 it opens the

  <Desc / Clms Page number 25>

 original attraction circuit of relay 460. The answering subscriber S is now connected to the junction, in both directions, via the conversation wires marked in reinforced lines. The supply current is supplied to the subscriber S by the line relay 550, the supply current for its correspondent is supplied by the public office.



   The release of the established connection with a trunk remains under the control of the local subscriber. At the end of the conversation when subscriber S hangs up, the line relay circuit 550 opens and this relay releases. In frame 551, relay 550 opens the bridge placed on wires 507 and 508 of the junction to release the devices of the central public office, at armature 522 it opens the circuit of release relay 560. After an oourt instant the relay 560 releases and opens the circuit of the relay 570 to the armature 561, to the armature 562 it reconnects the relay 504, working under the alternating current, to the terminals of the wires of the junction.

   Relay 570 releases after a short time and disconnects the earth from wire 534, it grounds wire 535 to armature 571, at armature 572 it opens the blocking circuit of relay 460 to cause the release of this relay which cuts the conversation circuit to the armatures 461 and 462, disconnects the earth of the wire 100 to the armature 463 to release the relay 103 and release the local line, closes the attraction circuit of the release relay 417 to the armature 456 and opens the circuit of the internal winding of relay 470 to armature 466. Releasing relay 470 at armature 471 causes the release of relay 530. Leotro / releasing magnet operates to return the switch in the normal position, at engagement springs 468 the circuit of relay 410 opens and this relay releases.

   The junction finder and junction equipment are now in the normal position, they can be used by another call.

  <Desc / Clms Page number 26>

 



   In the event of a fault, if, for example, a trunk finder cannot find the line that answers or if the incoming call is not answered, the time release device operates to release the trunk and the device after a certain time determined. Shortly after the inrush current from the public office is cut off, relay 500 releases to open the signaling circuit to armature 501, the time relay circuit 500 to armature 502 and the original attraction circuit of the time release relay. .580 to armature 503. When relay 590 releases armature 591 vibrates between its upper and lower contacts to keep relay 580 engaged for a set time.

   At this moment since the upper winding is short-circuited by the normally closed contact 469 the relay is delayed on release and therefore remains attracted under the action of the armature 591. When the amplitude of the vibrations of the armature 591 becomes insufficient to keep the relay 580 attracted, it releases.

   At armature 583, relay 580 opens the circuit of relay 570 which releases, at armature 581 and its contact on, it disconnects the earth of wire 533 to cause the release of relay 630, when the contact is at rest it puts wire 532 to earth to mark this junction as busy junction, for all incoming calls, in the junction distributor bank Relay 570 releases after a certain time, at armature 571 it disconnects the earth from wire 534 to allow the junction distributor to enter a junction for an outgoing call, at rest contact of armature 571 it connects earth to wire 535 to keep relay 630 engaged. In frame 572, relay 570 disconnects the earth of wire 526 to allow the release of the junction finder in the event that it has operated.



   Any subscriber with full service can send

  <Desc / Clms Page number 27>

 an outgoing call by picking up and sending the digits 01 and 02 depending on the group of trunks he wishes to reach.



  If we now assume that the subscriber S wishes to take a call to the public network using the first group of trunks, when he goes off-hook he connects to a free local trunk circuit. When the subscriber sends the digits 0 and 1, after having received the invitation to transmit, the brushes of the local connector engage on the bano contacts 234, 235, 236 and 237 as described above. .

   If there is no other local subscriber making a call to the public network at this time, relay 200 of the local connector and relay 664 of the junction distributor release in the following circuit: positive at armature 251 , armature 222 and its contact at rest, lower winding of relay 200, contact at rest and armature 891, brush 226, bank contact 235, wire 635, armature 624 and its contact at work, winding of relay 663, lower and upper winding of relay 664, armatures 683 and 690, negative.



  Relay 663 is a marginal relay, it does not draw in series with the top winding of relay 664. Relay 200 at armature 206 grounds wire 635. Relay 664 attracts if the junction distributor is not in service, at armature 680 it disconnects the negative of chain control relays 661 and 662 of group 2, at armature 681 it connects the negative of armature 675 through the lower winding of the relay 664 to cause the attraction of the marginal relay 663. To the armature 676 the relay 663 by attracting, connect the test circuit of the brush 616 of group 1 to the relay 640 and to the electronic control magnet 619.

   At armature 677, relay 663 prepares the circuit of relay 640, at armature 678 it places wire 639 to earth to mark the calling line as a busy line in the junction finder bench, finally to the armature 679 he puts the wire 645 at the

  <Desc / Clms Page number 28>

 earth to mark the group comprising the calling local line, in the junction finder banks.

   As long as the brush 616 is engaged on a grounded bank contact the own control circuit of the electromagnet 619 is closed and the starting relay is cut off to prevent it from being energized. when brush 616 engages on a bank contact where a wire ends, such as wire 534, which is not earthed the short circuit of relay 640 is open and this relay therefore draws in series with the electronic control magnet. The control electromagnet being marginal does not attract in series with relay 640.



  Relay 640 on pulling, armature 641 again grounds wire 479 to cause relay 450 to pull into the junction finder. At armature 642, relay 640 opens the control circuit for electromagnet 619, at armature 645 it attracts relay 650. Relay 640 remains drawn in the circuit which includes resistor R, the switch spring and the winding of the electro magnet 619.



   The trunk finder works in principle in the same way as that which has been described for an incoming call and places the caller at a trunk such as line 507-508. when a free junction is found the invitation tone to be transmitted from the public office is sent on the conversation threads of the junction and when the subscriber S hears it he sends the number of the desired subscriber granted to the public office , relay 550 to armature 551 repeats the pulses on the wires of the junction to operate the public office devices which complete the connection in the well known manner. Relay 560 remains engaged while sending pulses.

   When the called subscriber from the office picks up the conversation can begin, it will go on

  <Desc / Clms Page number 29>

 the wires marked in solid reinforced lines. At the end of the conversation, when the subscriber S hangs up his receiver, the line relay 550 releases and causes the release of the junction finder in the manner indicated previously, at armature 551 it opens the circuit to the public office to free the connections. automatic switches of this office.



   If all of the group 1 junctions are occupied for inbound and outbound communications all ground connections are cut to wire 535 to open the circuit of relay 620 which is normally drawn. Relay 620, by releasing at armature 621 gives a stop point to the junction distributor by disconnecting the ground of the bench, because it will be remembered that all the individual wires of the junctions, such as wire 534, are earthed when the jonotion is in use.

   At armature 624, relay 620 disconnects reports 663 and 664 and puts wire 635 to earth to occupy the output contacts of the banks of the local connector for this group of junctions At armature 622, relay 620 puts the wire 632 to earth through the lower coil of the relay 620 to attract the relay 230 of the local connector in the event that an outgoing call has been made by a local subscriber, and in the case where the local connector has been brought in this position when the last trunk of this group was entered for an incoming call. In these conditions, preference is given to the incoming call and the busy tone is transmitted on the line of the local subscriber. When he hears this tone, the local subscriber releases the local connector as mentioned previously.

   As soon as one of the group 1 junctions becomes free, the common occupancy wire 535 is grounded and the common occupancy relay 620 pulls in to remove, at the armature 624, the occupancy indication.



   In order to describe the blocking circuits of

  <Desc / Clms Page number 30>

 junctions and to show how a local subscriber can transfer communications with the public network from: a local line to another local line it will be assumed that the line of the set S is connected to the junction shown in fig. 4 and 5 and that the subscriber S wishes to transfer the call to the station S2. In this case the following relays are drawn: 410, 460, 470, 530, 550, 560, and 570.



  The subscriber S then pushes his push button PB in order to block the connection to the junction, in doing so he connects a ground on wire 102 to unbalance the relay 510 by short-circuiting its lower winding, The relay 510 attracted therefore while the relay 550 remained attracted by means of its upper winding. On armature 511, relay 510 establishes the circuit of relay 520 which attracts at the first beat. Relay 520 only closes its armature 525 which bypasses its lower winding.



  When the subscriber S releases the push-button PB, the relay 510 releases, at the armature 511 it removes the short-circuit placed at the terminals of the lower winding of the relay 529, this relay then attracts at the second time, at l 'armature 521 opens the conversation circuit, at armature 522 it opens this same circuit at another point and bridges the resistance R at the terminals of the windings of relay 550, at armature 523 it completes the circuit of attraction of relay 400 and at frame 524 it opens its initial circuit of attraction. Relay 400 to armature 401 grounds wire 498, to armatures 402 and 403 it bridges relay 480 across the calling subscriber loop and to armature 404 it transfers the circuit from relay 530 to check relay 480.

   Relay 480, pulling, to armature 481 grounds wire 499 to cause starter relay 990 to attract if the incoming distributor has preselected an incoming junction circuit, to armature 482 it connects negative through the

  <Desc / Clms Page number 31>

 relay 490 to mark the junction in the arrival finder, at armature 483 it keeps relay 530 attracted.



   In the inlet distributor, fig. 9, a busy incoming connection circuit is indicated by a ground on the ground wire 997 which extends to the brush 977 to operate the electro-magnet 972 according to its own control circuit. The electromagnet therefore moves its brushes forward until there is no earth on the ground wire of the junction circuit to which it is associated. Relay 990 attracts when wire 499 is grounded if brush 977 is on a bank contact that is not connected to earth, but since the electro magnet 972 is marginal it does not attract in series with relay 990 and resistor R which is to the right of relay 990.

   At armature 991, relay 990 opens the preselection circuit as well as its initial attraction circuit, so the relay remains attracted in series with resistor R and the control electro-magnet 972. At armature 992 relay 990 completes the attraction circuit of relay 980, at armature 981 relay 980 prepares the test circuit of the arrival finder, at armature 982 it closes the control circuit of electromagnet 790 of the seeker, at armature 983 it causes relay 970 to attract. The electro magnet 790 of the researcher attracts when its circuit closes at armature 982, it places itself in a position preparatory to the advancement of the arrival finder's brushes , at contacts 791 it closes the attraction circuit of relay 720.

   At the armature 721, the line relay 720 opens the circuit described above for the attraction of the electromagnet 790 of the searcher, therefore the latter releases and opens the circuit of the relay 720 to the armature 791. This interaction between the electromagnet 790 and the relay 720 continues until the brush 796 of the arrival finder has found

  <Desc / Clms Page number 32>

 the marking polarity applied to its test contact through the winding of relay 490.



   As soon as this is the case, relay 490 draws in series with relay 730 and the lower winding of relay 720 into the following circuit: positive taken through lower winding of relay 720, normally closed contacts controlled by the armature 731, top winding of switching relay 730, wire 995, brush 975, armature 981, brush 974, wire 994, test brush 796, wire 488, armature 482, cut-off relay bearing 490, negative. The relay 720 remains attracted in this circuit to avoid any subsequent movement of the arrival finder, while the switching relay 730 attracts to close its armature 734 alone which attracts the relay 740 and, through the springs of engagement 719, relay 750 also.



   Relay 740 at armature 741 earths ground wire 997 so that this junction circuit can no longer be grasped, at armature 742 it opens the control circuit of relay 720 and prepares a new circuit. attracting relay 720, at armature 743 it closes the circuit which passes through the lower winding of relay 730 to cause the latter to attract completely. The relay 750 on attracting, to the armature 751 sends the invitation tone to be transmitted to the calling subscriber at the time of the complete attraction of the relay 730 via the wire 72, the armatures 813 and 842, of the capacitor, of the wire 934 and of the lower conversation wire represented by a reinforced line.

   At armature 753, relay 750 closes the circuit of the lower winding of relay 730 so that the latter attracts the remainder of its armatures; to armature 731 it connects the two windings of line relay 720 in bridge on the calling loop and completes the circuit for sending the invitation tone to be transmitted. At the frame

  <Desc / Clms Page number 33>

 732 it prepares at one point the circuit of relay 860, at armature 753 and its contact at rest it disconnects the earth of the common occupancy wire 998, at armature 733 and its contact for work it prepares the switching relay circuit 880. At armature 735, relay 730 grounds test brush 796 to keep relay 490 engaged and to occupy this junction with respect to all other incoming seekers.



   In the junction finder relay 490 draws in the circuit described previously, at armature 491 it disconnects the earth of wire 499 to open the circuit of relay 990 of the incoming distributor. At armatures 492 and 494 the relay 490 disconnects line relay 480 from wires 497 and 496, it therefore releases, at armature 493 it is blocked by wire 488 and armature 735 earthed, at the armature 495 it establishes a new blocking circuit for relay 530.



   When the relay 990 releases in the inlet distributor of fig. 9, at armature 991 it re-establishes the pre-selected air-cured of the electro control magnet 972, at armature 992 it opens the circuit of relay 980. Relay 980 when releasing at armature 981 opens in one point the initial test circuit, at armature 982 it opens at one point the control circuit of the electro-magnet of the searcher and at armature 983 it opens the circuit of relay 970 and completes the circuit maintaining the control electromagnet 972 in action position / via armature 971,

   After a certain time the relay 970 releases and at the armature 971 opens the blocking circuit of the electromagnet 972 to allow the latter to operate and to preselect a free incoming junction circuit.



   When subscriber S hears the invitation to transmit tone which indicates to him that an incoming trunk circuit

  <Desc / Clms Page number 34>

 free has been selected it transmits the number of station S2, ie the digits 9 and 1. The transmission of the first digit releases the relay 720 nine times and on each release the electro-magnet 824 operates. A bypass of the pulse circuit extends through the lower winding of relay 750 to block that relay during the send period. The brushes of the inlet connector are therefore brought to the ninth level. At the first step of deceleration the engagement springs 719 open the initial circuit of the relay-series 750.

   Shortly after the sending period the relay 750 releases to disconnect the invitation tone to be transmitted from the calling line to the armature 751, finally to the armature 753 it transfers the pulse circuit of the electromagnet of ascent 824 to the electro magnet of rotation 817.



   The emission of the second digit releases once the relay 720 which transmits a single impulse to the relay 850 and to the rotation electromagnet 817 thus the brushes turn by one step and engage on the bank contacts 867, 868, 869,856 and 854. The relay 860 attracts in series with the rotation electromagnet 817 and remains attracted during the send period. On armature 851 and its contact at rest, relay 850 opens the circuit of switching relay 880, on armature 851 and its contact on contact it closes the occupancy test circuit to occupancy relay 870 , at armature 853 it makes its own circuit and that of electromagnet 817 independent of the position of armature 875 of occupancy relay 870.



   If the S2 extension line is busy wire 269 is grounded and the busy relay 870 is pulled, at armature 871 it connects the busy tone to the lower talk wire of the incoming trunk circuit.

  <Desc / Clms Page number 35>

 



  At armature 872, relay 870 transfers the circuit of relay 860 to relay 840, at armature 873 it prepares its own blocking circuit, at armature 874 it opens the circuit of switching relay 880, at armature 875 it opens the pulse circuit to relay 850 and the electromagnet 817. Shortly after the end of the sending, relay 850 releases to open the initial attraction circuit of the occupancy relay 870 on contact with the armature 851, with the normally closed springs controlled by armature 851, it completes the blocking circuit of occupancy relay 870 by an earth taken from armature 715.



   When subscriber S hears the busy tone, he presses. the push-button PB to activate the differential relay 510 again, this time short-circuiting the lower winding in series with the lower winding of the line relay 720. The two-stroke relay 520 being attracted, the attraction of armature 511 at this moment completes the circuit of relay 540 which to armature 541 connects a bridge comprising resistor R, on the winding of line relay 550; to armature 542 it provides a new blocking circuit for two-stroke relay 520 using armature 511 grounded. When the subscriber S releases the push-button PB releases the differential relay 510 / and at frame 511 opens the blocking circuit of the relay 520 and the circuit of the relay 540.

   Relay 520 by releasing at frame 522 opens the initial blocking circuit borrowing the windings of line relay 550, at armature 523 it opens the circuit of relay 400 and at armature 524 it prepares the initial attraction circuit of relay 520. Relay 400 by releasing at armature 401 disconnects the earth of wire 498, at.armatures 402 and 403 it disconnects relay 720 and at;

  armature 404 it keeps relay 530 attracted by means of an earth taken from the armature ,, 471. The

  <Desc / Clms Page number 36>

 relay 540 releases shortly after releasing relays 520 and 400, at armature 541 it opens the bridge placed on the windings of line relay 550, but as the subscriber's loop remains connected to these windings the relay remains in actuated position.



   In the arrival finder relay 720 releases and at armature 721 opens the circuit of relay 740 which releases after a certain time, at armature 741 it disconnects one of the earths of ground wire 997 and completes the circuit - attracting the release electromagnet 717. At the armature 745, the relay 740 disconnects the earth from the blocking wire 724 to release the relay 730 which at the armature 731 again prepares the test circuit , when the armature 733 is on contact it opens the blocking circuit of the occupancy relay 870, when the contact is idle it puts the common occupancy wire 998 to the earth, at the armature 735 it disconnects the earth from the wire 994 to release relay 490 of the junction finder and to disconnect the earth of wire 488.

   Relay 870 by releasing to armature 871 opens the circuit for sending the busy tone. The release electro-magnet 717 attracts via a ground taken at the engagement springs 718 and returns the input connector to the normal position, to the engagement springs 719 the initial attraction circuit of the relay - 750 series is prepared again. The incoming trunk circuit is now available for further calls.



   The line from set S is reconnected to the junction and when the blocking bridge placed at the frame 541 is removed following the release of relay 540, subscriber S notifies the subscriber of the central office that subscriber S2 is busy. The conversation having continued, it will be assumed that subscriber S wishes to transfer the call to another line.

  <Desc / Clms Page number 37>

 local or to line S2 again, to do this subscriber S presses pushbutton PB to trigger relays 510, 520, 400, 480, 990,980, 720, 730, 740, 750 and 490 and the electromagnet 790 as described above.

   when the subscriber S hears the invitation to transmit tone, he emits the digits 9 and 1 to bring the brushes of the connector to the contacts of the called line in the manner which has been previously described.



   If we now assume that the line of extension S2 is free instead of being busy as mentioned above, the busy relay 870 does not attract and therefore the switching relay 880 operates when the relay series 850 releases shortly after sending the rotation pulses. The attraction circuit of the switching relay 880 includes: the positive to the armature 715, the lower winding of the relay 880, the wire 269, the lower winding of the individual line and cut-off relay identical to the relay 103, the negative. The individual line and breaking relay associated with the line of station S2 attracts in the usual way in series with the switching relay 200.

   The relay 880, attracting, to the armatures 882 and 883 connects the inrush current to the line of the station S2 at the same time that it prepares the conversation circuit at a point, to the armature 884 it establishes the return circuit call, at armature 886 it puts brush 893 to the ground to keep the individual line and cut-off relay in operation and to keep the called line occupied, at armature 887 it completes its blocking circuit clean through armature 743 grounding, armature 714 and wire 725; finally at the armature 888 it opens the opening of the rotation electromagnet 817.



   When the called subscriber answers the relay 830 draws in the line bouole and cuts the circuit sending the

  <Desc / Clms Page number 38>

 inrush current. Relay 830 first closes its contact 836 to establish the circuit which will allow it to fully actuate the rest of its armatures, at armature 831, relay 830 opens its initial attraction circuit, to armatures 831, and 832, 833 and 834 it completes the conversation circuit which borrows the wires represented in reinforced taits, from the armature 834 and its contact at rest it opens the circuit for sending the inrush current, finally at armature 835 it opens the return call circuit. Subscriber S and subscriber S2 are now talking on wires 101, 102, 513, 514, 512, 515, 497 and 498, the wires shown in reinforced lines of the incoming trunk circuit, wires 267 and 268.

   The junction is kept in service by the bridge which comprises the resistor R of FIG. 5.



   Subscriber S can reconnect his line to the junction in the manner described previously, i.e. by pressing the push-button, but in order to transfer the call, subscriber S notifies the subscriber S2 from what the public network requests. Subscriber S2 presses his pushbutton PB, which grounds positive wire 268, to unbalance relay 770 of fig. 7. The relay 770 attracts, at the armature 771 it closes the attraction circuit of the relay 780 at the first time. Relay 780 actuates its armature 784 alone at this time which bypasses its upper winding.



   When subscriber s2 releases the push button, earth is removed from wire 268 and relay 770 releases. In frame 771, relay 770 removes the short-circuit of the upper winding of relay 780, the result of which is that this relay energizes the rest of its armatures, attracting at the second time. At armatures 781 and 782, relay 780 disconnects the earth of wire 933 to give a stop point to the distributor transfer brush, at armature 782 it puts wire 693

  <Desc / Clms Page number 39>

 to earth to attract relay 666 of the junction distributor if it is not in service, at armature 785 it opens its initial attraction circuit, finally at armature 785 it puts the wire 727 and brush 893 to ground to keep wire 269 connected to ground.



   Relay 665 is marginal and does not attract in series with the two windings of relay 666. Relay 666 by attracting, at armature 683 disconnects the negative of the windings of relays 662 and 664, at armature 684 it disconnects the negative taken through the armature 675 and its contact at rest, the armature 681 and its contact at rest, the armature 684 and its contact at work and the winding of the relay 666, to cause the attraction of the relay marginal 665. As the fittings 683 and 684 are attracted, the trunk distributor cannot be seized for incoming or outgoing calls while a call is being transferred. By pulling relay 665, armature 682 grounds wire 693 to draw starter relay 910 into the transfer distributor.

   In the armature 911 the relay 910 completes the own control circuit of the electromagnet 968 in the event that the brush 913 reaches an earthed contact, finally to the armature 912 it short-circuits the relay 920 of switching on if the brush 913 is earthed.



   If we assume that the broom 913 is engaged on a bano contact which is grounded, the electro magnet 968 works as a buzzer until the broom 913 finds no more ground, at this moment the short- Relay 920 circuit is removed, so this relay draws in series with the electro magnet 968. Relay 920 to armature 921 connects the busy tone to wire 934 through brush 914 to transmit the tone. to the two subscribers S and S2 and to notify them that the communication is in progress

  <Desc / Clms Page number 40>

 of transfers At armature 922, relay 920 completes a new blocking circuit for itself through resistor R, at armature 924 it completes the circuit of relay 950.

   Relay 950 pulling armature 951 earths wire 938 through brush 918 to hold arrival finder relay 740 attracted; as a result of the presence of a block which ballasts the on contact of the armature 952, this contact vibrates and intermittently closes the circuit passing through the lower winding of the relay 960. The relay 960 is delayed on attraction it does not. will therefore not attract immediately under the effect of the intermittent closing of the contact at work and of the armature 952. The block 955 which ballasts the armature 952 vibrates the latter for a certain time before the contact. is closed for a time long enough to attract relay 960.

   In frame 961 relay 960 grounds wire 937 through brush 917 to mark the vertical junction finder bench through inlet connector brush 895 and of wire 154. At armature 962 relay 960 grounds wire 936 to mark junction finder bench contacts 477 through incoming connector brush 894 and wire 485. armature 963 relay 960 completes the attraction circuit of relay 710 and relay 440, at armature 965 it opens the circuit of electromagnet 958, at armature 967 it closes the circuit of at = traction of time relay 930 via earth taken at armature 924 and armature 944.

   At armature 931, relay 930 completes the attraction circuit of relay 940 by means of the earth taken at armature 966 and armature 923, it also completes the circuit of the upper winding of the relay 960 which keeps it attracted.



  The Block which ballasts the armature 931 makes it vibrate when releasing the relay 930 alone.

  <Desc / Clms Page number 41>

 is lying. At armature 942, relay 940 closes its blocking circuit specific to armature 924 which is earthed; at armature 943 it opens the initial attraction circuit of relay 960 and finally at armature 944 it opens the circuit of relay 930 which consequently releases and makes its armature 931 vibrate.



  This vibrates for a determined time under the action of the unit which ballasts it to allow the transfer of the communication.



   The attraction circuit for relays 710 and 440 is as follows: positive to armature 963, brush 915, wire 935, top winding of jonotion release relay 710, brush 793, wire 487, armature 453, armature 405, coils - ment of transfer relay 444, negative. Relay 710 first actuates its armature 713 to complete its blocking circuit, through its lower winding through the earth to armature 743, and to fully actuate the remainder of its armatures.

   At armatures 711 and 712, relay 710 disconnects line relay 720 from the subscriber's line to trigger the release of relay 720, at armature 714 it opens the blocking circuit of switching relay 880 which consequently releases, to the armature 715 it opens the circuit of the lower winding of the relay 880 finally to the armature 716 it opens the pulse circuit and the initial attraction circuit of the release relay 740 which now remains attracted through the intermediary of wire 938 to ground. Relay 880, by releasing, at armature 885 opens the blocking circuit of relay 830 which also releases, at armature 886 it disconnects one of the earth connections of brush 893 which however remains connected to the positive by the 729 wire grounded.



   In the junction finder of fig. 4 the relay 440 draws in series with the relay 710 in the circuit described above, at the armature 441 it transfers the test circuit from the brush 425 to the brush 426; at frame 444 he puts - ,, the

  <Desc / Clms Page number 42>

 wire 527 to ground, and opens the circuit of the lower coil of relay 470 to cause that relay to release.



   Relay 470 by releasing at armature 473 opens the blocking circuit of relay 460, which therefore releases, at armature 469 it again short-circuits the upper winding of relay 580. Relay 460 releases after a short moment, at armatures 461 and 462 it disconnects the line of the calling subscriber S, at armature 463 it disconnects one of the earth connections of wire 100, at armature 464 it completes the attraction circuit of the relay 430 by means of the wire 487 earthed, at the armature 465 it completes the circuit of attraction of the release electromagnet 417.



   The relay 430 by attracting, to the armature 431 establishes another bridge, comprising the resistance R, at the terminals of the windings of the relay 550 in order to maintain, the jonotion blocked, to the armature 432 it is blocked on it - even with the grounded wire, at the armature 434 it puts the wire 479 to the ground, at the armature 435 it disconnects the earth from the wire 528 and puts the wire 529 to the ground. As a result of the operation of the release electromagnet 417 the junction finder brushes are returned to the normal position, thereby the engagement springs 468 open the circuit of the transfer relay 410 which consequently releases. By releasing the transfer relay 410, at armature 412 completes the traction circuit of relay 450, at armature 414 it prepares its own attraction circuit.



   The relay 450 by attracting, to the armature 452 completes the circuit of the lower excitation winding of the relay 470, to the armature 453 it opens the initial circuit of attraction of the relay 440, this relay however, remains attracted by ltinter- / '

  <Desc / Clms Page number 43>

 middle of wire 487 grounded and armatures 464, 442, 432 and 405, At armature 454, relay 450 again closes the circuit of the ascent electromagnet 416, at armature 455 it is blocked itself to 434 wire grounded. The ascent electromagnet operates and advances the brushes step by step by cooperating with the relay 420 as previously described until the vertical brush 428 finds the marked vertical bench contact, at which time the relay 410 attracts and transfers the control circuit to the rotation electromagnet.

   The relay 420 remains attracted until its circuit is opened by the ascension electromagnet and the relay 410. The control relay cooperates with the rotating electromagnet in the manner previously described until the control brush. transfer 426 meets the marked bank contact, at this moment the time relay 470 attracts, At the armature 472 the relay 470 opens the circuit of the rotation electromagnet 415 and causes the relay 460 which remains blocked by through armature 473, the junctio finder has been actuated again to operate the search for the contacts marked by the transfer distributor, and for the fact that the incoming connector is engaged on the bank contacts which lead to feels the wires of the line from station S2,

   the connection finder is also brought to the bank contacts to which the same wires end.



   The relay 460, by attracting, to the reinforcements 461 and 462 completes the conversation circuit which borrows the line from the station S2, the wires 267 and 268 and the brushes 422 and 423.



  At armature 463, relay 460 earths wire 269 to keep line S2 occupied and so that the individual line and cut-off relay remains engaged, at armature 464 it opens the circuit of relays 440 and 430. Releasing relay 440, at armature 441 opens the circuit of relay 470 which remains

  <Desc / Clms Page number 44>

 attracted through its lower winding, to the armature 444 it connects an earth to the lower energizing winding of the relay 470 through the armature 466 and its contact to work. On contact with the armature 444, the relay 410 opens the blocking circuit of the two-stroke relay 520 which releases.

   Relay 520, on releasing, at armatures 521 and 522 completes the conversation circuit towards the junction and removes one of the bridges placed on relay 550, finally at armature 523 it opens the circuit of relay 400.



   The relay 430 releases after a short time, in the frame 431 it removes the last bridge placed on the windings of the relay 550 so that the latter is kept drawn into the circuit of the line. subscriber S2. At armature 434, relay 430 disconnects the earth of wire 479 to release relay 450. Relay 400, by releasing, at armature 401 disconnects the earth of wire 498 to release relay 780, at armatures 402 and 403 it disconnects wires 497 and 496, at armature 404 it transfers the blocking circuit of relay 530 to earth at 471. Relay 450 releases after a short time and at armature 451 opens the circuit. initial attraction of relay 470 which however remains attracted in the circuit of its lower winding by means of the armature 444 earthed and the armature 466.

   At armature 454, relay 450 opens the original attraction circuit of relay 460 which remains attracted in the circuit of armatures 473 and 572. Communication has therefore been transferred from the line of station S to the line of station S2 and the searcher of junctions are under the same conditions as if subscriber S2 had answered the call.



   In the searcher entering the relay 780 releases, at the reinforcements 781 and 782 it puts the wire 933 to the ground for

  <Desc / Clms Page number 45>

   oor-orouiter relay 920 of the transfer distributor.



  At armature 782, relay 780 disconnects the earth of wire 693 to release relays 665 and 666.



   In the junction distributor the relays 665 and 666 release and the relay 665 at the armature 682 disconnects the earth of the wire 692 to release the relay 910 of the transfer distributor. Relay 666, when released, to armatures 683 and 684 prepare circuits which will allow the other chain control relays to work.



   The relay 910 of the transfer distributor releases, at the armature 921 it opens the circuit of the relay 920 which releases following the establishment of a short circuit, as has been described previously, or when the armature 912 is activated. At armature 921, relay 920 disconnects the busy tone from wire 934, at armature 922 it opens its own blocking circuit at one point, at armature 923 it opens the circuit of relay 960 which releases after a at certain times, at armature 924 it opens the circuit of relays 940 and 950. Relay 950 releases the first, at armature 951 it disconnects the earth of wire 938 to allow the release of relay 740 from the connector. arrival, at armature 952 it opens the circuit of the lower winding of relay 960.

   Relay 940 releases shortly after] Relay 950, at armature 941 it puts armature 951 to earth but only after it has been released by relay 950, Relay 960 when releasing at armature 961 disconnects the ground of wire 937 to remove the marking earth of the brush 895, at the armature 962 it disconnects the earth of the wire 956 to remove the marking earth of the wire 894, at the armature 963 it disconnects the earth wire 935, at armature 965 it prepares the fired air for electromagnet 968. The transfer distributor has returned to the normal position and can be used for subsequent transfers.

  <Desc / Clms Page number 46>

 



   The relay 740 of the incoming junction circuit releases when the earth is removed from wire 938 in the transfer distributor, to the armature 741 and its contact at work it disconnects one of the earth connections of the ground wire 997 At armature 741 and its contact at rest, relay 740 completes the circuit of the release electromagnet 717, at armature 742 it prepares the control circuit of relay 720, at armature 743 it disconnects the earth of the wire 724 to cause the release of the relays 710, 730, 830 and the relays 810 and 820, and 860 stil is attracted; at frame 744 it opens the pulse circuit.

   When the relays 710 and 730 release the common occupancy wire 998 is again earthed through the armatures 715 and 733. The operation of the releasing solenoid returns the connector to the normal position and the shaft springs 718 remove the last connection to earth of the guard wire 997. Subscriber S2 can block communication with the public network and initiate a local call, if he wishes he can transfer communication with the network public to another local subscriber as described above.



   The transfer distributor is provided with a time release device which operates for a certain determined time after releasing the relay 930, it causes the release of the incoming junction circuit in the event that for some reason the transfer does not. would not have been carried out. A certain time after releasing the relay 930, the weighted armature 931 stops vibrating and the relay 960 releases which causes the release of the incoming junction circuit as previously described.



  At armature 963, relay 960 disconnects the earth from wire 935 to release relay 710 and relay 440 if it has attracted and to allow the finder to be released from /

  <Desc / Clms Page number 47>

 junction. If the relay 440 does not attract, the third-party ring finder is not released automatically, it returns to idle when the subscriber hangs up his receiver.



   The incoming trunk circuit is also provided with relays 810 and 820 for the split call, they work like relays 270 and 280 of the local connector so that the incoming connector can ring subscribers, such as subscribers S1 and S3, which have their ringtone connected to the negative wire of their line. The operation of the assembly will be understood without difficulty by referring to the description of the operation of the local connector.



   Subscribers may be deprived of the possibility of taking and receiving from Home communications with the public network, the stations of these subscribers are not provided with a push button, moreover they have a negative polarity connected through a resistor in contact with a bench accessible to the brush 174. For example, as shown in Z, FIG. 1, it can be assumed that bank contact 143 is connected to resistor and negative Z instead of to wire 152.

   In this case the line of stations S and S2 is single-service so that if station S wants to take a call to the published network or answer a call coming from it, relay 240 draws into the following circuit: positive to any of wires 639, 637 or 646 depending on which chain control relays attracted, brush 227, armature 208, transfer relay lower winding 240, wire 195, brush 174, bano contact 145, resistor Z, negative. Relay 240 attracts, at armatures 241 and 242 it opens the circuit of line relay 210, at armature 243 it completes its own blocking circuit through its upper winding and via the earth taken at l. 'frame 253.

   Relay 210.

  <Desc / Clms Page number 48>

 on releasing, the armature 211 opens the circuit of the relay 250 which releases and causes the release of the local junction circuit as previously described. at
Restricted service subscribers have / at their disposal a station equipped with a push-button, their line is equipped with a connection, identical to that shown in Z, which ends at their individual bench contact. They can however be connected to the public network, but only if the communication has been transferred to them by a full service subscriber. This transfer takes place as described above.



   The changeover switch shown in fig. 10 is in reality a subscriber line having special characteristics which allow it to answer incoming calls from the public network when the traffic is of such importance that it is desirable to have a single person answering the calls and who transfers it to the requested correspondents. As can be seen when the IK information key is activated, the operator's station is connected to the local equipment through wires 277 and 278.



  The TK transfer key replaces the PB push-button, it allows the operator to control the operation of differential relays incorporated in the junction circuits for transferring and receiving transferred communications, in conjunction with the public network, on wires 277 and 278. As has been described, local subscribers who wish to call the operator send the digits 0 and 3 which activate the local connector, which is connected to the operator's line. and operate the RB bell, fig. 10.



  The operator activates the information key and picks up what establishes the local connection circuit. As has been said for local subscribers, the operator by activating

  <Desc / Clms Page number 49>

 the information key and call dial CD can establish connections to local lines by means of wires 277 and 278 and the local trunk circuit. In addition, the operator can block any local line by activating the blocking key o, that is to say by bridging wires 277 and 278, after which she can restore the information key to the normal position and answer any incoming call. As these local connections through wires 277 and 278 are established in the manner described for other local subscriber lines it would seem unnecessary to go into more detail.



   It can now be assumed that the operator must answer a call coming from the public network and that the signaling key SK in FIG. 10 is actuated and locked in the working position. Under these conditions the relay 1007 is disconnected to prevent the operation of the signals, common call on junction, the relay 1016 is connected instead of these so that during an incoming call the relay 1016 attracts and that in armature 1017 it closes the circuit of buzzer B which notifies the operator that an incoming call is pending.



   Only one release and response key, with two positions, and the associated relays 1030, 1044, 1050, 1060 and 1070 have been shown, but it is possible to provide the changeover switch with a second key and a second key. 'a second set of identical relays so that the operator can take care of more than one junction at the same time. When buzzer B is working, the attendant moves one of the two AS answer keys and picks up her receiver. The pull circuit of relay 1030 then closes and the inversion wires 1092 and 1093 are connected to the operator's station by means of the armatures 1031 and 1032 and the ITK information key.

   At armature 1033 the relay 1030 complete

  <Desc / Clms Page number 50>

 its blocking circuit through its upper winding and the attraction circuit of the common relay 1020 by means of the upper springs 1024. At the armature 1036 the relay 1030 completes the attraction circuit of the line relay 1050. The relay 1020 attracts in series with the top coil of relay 1030 and armature 1021 disconnects earth from the rest of the response keys to prevent the attraction of another connection relay, such as relay 1030. This arrangement therefore makes it necessary to put the first response key back to rest before actuating a second key in order to operate the connection relay associated with this second key.

   The relay 1050, attracting, to the armature 1052 connects the individual connector 1095 to the common wire 1098 and to the armature 1055 it puts the wire 1097 to the ground to make the relay 668 of fig. 6 attract, since *. at this time relay 630 is drawn due to the arrival of a call on the incoming trunk. Relay 668 attracts and operates the trunk distributor which searches for the incoming trunk in the manner previously described.



   As a result of the operation of the junction finder start relay 450, the finder brushes are actuated as before, they stop opposite level 0 since the vertical brush 428 meets an earth on the tenth vertical bank contact, at this point the inversion relay 410 attracts and blocks. The brushes then rotate under the action of the rotation electromagnet 415 as before until the test brush 425 finds the marked bank contact, the relay 470 then draws in the following circuit: positive to the armature 589, common wire 1098, armature 1042, armature 1052, wire 1095, bank contact 448, brush 425, bank contact and armature 441, contact

  <Desc / Clms Page number 51>

 451, upper winding of relay 470, negative.

   Relay 470, by attracting, to armature 472 opens the circuit of the rotation electromagnet to prevent further rotation of the brushes and to attract relay 460 which at armature 463 sets brush 424 to earth to ground wire 1094 itself, which pulls relay 1040 of the pass-through switch; to armatures 461 and 462 - it connects the conversation wires to wires 1092 and 1093 through brushes 422 and 423. The relay 1040 by drawing to armature 1042 disconnects the earth of wire 1095 to open the circuit of the upper winding of relay 470 but the latter remains drawn into the circuit of its lower winding alone.

   To armature 1043, relay 1040 connects wire 1094 earthed to the winding of relay 1050 via armatures 1035 and 1053 to keep relay 1050 attracted independently of the position of the MC springs. Closing of contact 1044 of relay 1040 turns on the supervision lamp SL which indicates to the operator that the connection has been established, at armature 1045 this same relay disconnects the earth of wire 1097 to release relays 667 and 668 of the junction distributor.



   The conversation circuit borrows the wires shown in reinforced lines 1077, 1078, 1087, 1092, 1093 and the conversation wires from the junction. Power to the attendant set is supplied by line 550, while network subscriber power is supplied from the central office battery.



   If the attendant wishes to answer a second incoming call before having completed the first communication, she returns her answer key to the normal position, which releases the relays 1020 and 1030. When the relay

  <Desc / Clms Page number 52>

   1030 releases. A blocking circuit is established on the conversation wires 1092 and 1093 with normally closed springs controlled by armatures 1031 and 1032. The blocking circuit is extended through armature 1041, the resistor R and armature 1051 to keep line relay 550 attracted.

   The attendant then activates her second answer key (not shown) thereby another trunk finder associated with the second incoming call connects to the operator's set in a manner identical to that described for the first call.



   In this case, the junction finder turns an additional step to mark a wire identical to wire 1095 and which is specific to this second response position.



   This wire leads in this case to the second level 0 bench contact accessible to the brush 425. If the attendant answers two calls in this way, she can block or transfer any of the incoming calls at will, because the resetting any of the answer keys to their normal position blocks the junction.



   It will now be assumed that the operator, after having spoken to the subscriber of the central office on the first trunk, wishes to transfer the call to set S.



   For this purpose it momentarily activates the transfer key TK which connects a free incoming junction circuit to this junction. The springs 1028 complete the attraction circuit of the relay 1060 at the first stage, it only aions its armatures 1062 and 1063, to the armature
1062 it short-circuits its lower winding through the earth taken from the armature 1054 and the armature 1072.

   At the transfer springs 1027, the earth is connected to wire 1078 and the following circuit is established: spring 1023 and contact at rest of the information key,

  <Desc / Clms Page number 53>

 wire 1088, armature 1032 and contact on, wire 1093, brush 423, armature 462, wire 514, lower winding of differential relay 510, normally closed contacts controlled by armature 522, lower left winding of the translating coil, winding bottom line relay 510, positive. The circuit which has just been described short-circuits the lower winding of the relay 510 which actuates its armature 511.

   At armature 511, relay 510 causes relay 520 to attract at the first step as before and when the transfer key TK is returned to the normal position, the differential relay 510 releases and removes the short-circuit of the lower winding of the relay. 520 to allow it to draw in the second beat, as before.



   In the changeover switch as a result of the opening of contacts 1028 of the TK transfer key, the transfer relay 1060 attracts at the second stroke the short circuit of its lower winding being removed, it attracts at the second stroke via of the earth taken from the 1054 armature and its two windings in series. At armature 1061, relay 1060 prepares the circuit of the second transfer relay 1070.



   Pulling relay 520 from the junction circuit causes the same effect as that described for blocking set S, i.e. the attendant establishes a connection to a local set - set S for example. , by means of an incoming trunk by sending the number of the called subscriber.



   When the subscriber S answers the operator speaks on the conversation threads represented in reinforced lines and she warns the local subscriber of what is requested from the public network, the local subscriber then actuates his push-button PB to do so. attract the transfer relay 770, the researcher

  <Desc / Clms Page number 54>

 of junctions first searches for this line and then connects to it in the manner previously described. When the junction finder relay 460 releases, the pass switch relay 1040 circuit opens and that relay releases. At armature 1044, relay 1040 turns off the supervision lamp to inform the operator that communication has been transferred, at armature 1043 it transfers the circuit of relay 1050 to the springs MS.

   The operator returns her answer key to the normal position and hangs up, thereby relays 1020, 1030 and 1050 release.



  When relay 1050 releases, at armature 1054, it opens the blocking circuit of relay 1060 which in turn releases.



   When the operator has called a local subscriber to transfer a call to him, she can return the answer key to the idle position before the subscriber has answered. In this case the relays 1020 and 1030 release, but the relays 1040, 1050 and 1060 remain attracted. when the local subscriber answers he hears the busy tone which he receives through the armature 1064 and the armatures 1041 and 1051 and the conversation wires shown in reinforced lines. He will immediately understand that he has been called by the operator and that he is requested from the public network.

   He then actuates the PB push button to transfer the communication without the attendant's help, when the junction finder is released and when it operates again the relays 1040, 1050 and 1060 release. when the call is transferred and the relay 1040 releases the supervision lamp SL goes off to inform the attendant that the communication has been transferred.



   The relay 1070 of the changeover switch is provided to release the relay 1060 so that the busy tone sent to the armature 1064, is not transmitted to the subscriber of the public office in the event that

  <Desc / Clms Page number 55>

 the subscriber first called by the operator does not answer or in the event that the operator wishes to transfer this call to a second local line instead of the first. for example, it will be assumed that the operator wishes to put the subscriber of the central public office connected to this junction in touch with a second local subscriber because the first does not answer or because when the first station has answered the the operator learned that the requested person could be reached at a second station.

   To call a second line, the operator again activates the TK transfer key to close the springs 1028, which attracts the relay 1070 at the first beat. Closing contacts 1027 earths wire 1070 which pulls relay 540. When the transfer key is reset the short-circuit of the lower winding of the transfer relay 1070 is removed. As a result, relay 1070 attracts at the second time to open contacts 1072. At these contacts, the blocking circuit of the first transfer relay 1060 opens and this relay releases. At armature 1064 relay 1060 disconnects the busy tone, at armature 1063 it opens the circuit of relay 1070 which also releases.

   Placing the transfer key in the normal position disconnects the key from wire 1078 to release relay 510. Relay 510, when releasing, at armature 511 opens the circuits of relays 520 and 540. Relay 540 being delayed on release, relay 520 first releases to reconnect, at reinforcements 521 and 522, the operator line to the subscriber line of the public network through the junction wires. At armature 523, relay 520 releases relay 400. When relay 400 releases, at armatures 402 and 403 it disconnects the junction wires from the incoming junction circuit, at armature 401 it disconnects the earth

  <Desc / Clms Page number 56>

 of wire 498, at armature 404 it keeps relay 530 attracted.

   The relay 540 releases after a short time and opens the blocking bridge to the frame 541 to allow the conversation between the operator and the subscriber of the public central office.



   In the arrival finder the line relay 720 releases when the armatures 402 and 403 open to cause the release of the incoming junction circuit as described previously. The attendant is reconnected to the trunk and the relays are in the same state as when the attendant first answered the call from the public network. In order to call the second line, the attendant once again activates her transfer key TK to connect a free incoming trunk circuit to her set after which she places the incoming connector on the second line as we do. 'previously described. The second subscriber accepts the communication by actuating the push-button, which transfers the call to his set as described above.



   The operator can release a communication with the public network by restoring the answer key in position / rest and by activating it in the released position to open the blocking circuit of the line relay 1050.



  Relay 1050, on releasing, to armature 1051 opens the blocking circuit placed on the wires of junction 1092 and 1093 to cause the release of the junction finder. The release of the junction finder causes the release of the relay 1040 which turns off the lamp L to inform the operator that this finder has returned to rest. From the above it can be seen that by the use of incoming switches the operator can transfer communications coming from the public network even if all the circuits

  <Desc / Clms Page number 57>

 local joints are busy.



   The incoming connectors are designed to make it possible to offer communications to busy lines and to allow placing on hold on occupied lines when these incoming connectors are put into service by the operator. It can be assumed that the inlet connector shown in fig. 8 was entered by the operator and put in position on the line of sets S2 and S3 currently occupied., The junction finder relays, the arrival finder and the arrival connector work in the same way as that which was previously described and when the arrival finder works, the circuit of relay 860 closes as follows:

   positive through the lower winding of relay 860, idle contact and armature 872, wire 726, armature 732, brush 795, wire 486, brush 427 of the junction finder, bank contact 476, wire 1096, armature 1034, resistanoe Rl , negative. At armature 861, relay 860 closes its blocking circuit, at armature 863 it short-circuits the lower winding of relay 870 to make this relay delayed on release. The relay 870 attracts as it has been said previously when the called line is busy, at armature 871 it connects the busy tone to the operator line.

   At armature 872, relay 870 opens the initial attraction circuit of relay 860 and prepares the circuit of relay 840, at armature 873 it prepares its own blocking circuit, at armature 874 it opens the circuit from the switching relay 880 and finally to the armature 875, it opens the circuit for sending the pulses. When the series relay 850 releases after sending the pulses, the relay 870 is blocked by the earth of the wire of the called line. When the attendant hears the busy tone, she can either put the call on hold on this line, or wait.

  <Desc / Clms Page number 58>

 until it becomes free again or it can offer the call to the busy subscriber.



   Assuming first that the attendant puts the communication on hold on the busy line, it can be seen that when this line becomes free again the blocking earth is removed from brush 893, the result is that relay 870 releases. Relay 870 on releasing, at armature 871 suppresses the busy tone, at armature 874 it closes the pull circuit of relay 880 which releases to connect the call generator to the called line.

   The operation from this moment is identical to that described previously, when the subscriber answers the attendant asks him to take the call; in the case where Empress has restored her answer key to the normal position. the called party hears the busy tone which informs him that a communication coming from the public network is pending at his address, he takes this communication by actuating his push-button to release the junction circuit and to release and operate the junction finder again as described previously.



   If we now assume that the attendant wishes to offer the communication to the called subscriber who is busy, she then activates the COK offer key to ground wire 1096, which attracts relay 840 in the following circuit: positive to wire 1096, bank contact 476, brush 427, wire 486, brush 795, armature 732, wire 726, armature 872 and its contact at work, winding of offer relay 840, negative. To armature 841 the relay 840 connects a special tone on the upper conversation wire to warn local subscribers that the operator is listening on their line, to armature 842 it connects the busy tone, finally at armature 843 it makes attracts 5 - the relay

  <Desc / Clms Page number 59>

 830.

   In frames 832 and 833, the conversation circuit between the operator's set and the stations of busy subscribers is closed through the conversation threads shown in reinforced lines, and the operator warns the two correspondents that a call from the public network arrived at the address of one of them. Empress returns the COK offer key to the normal position and releases relay 840. This relay, by releasing, at armature 841 suppresses the special tone revealing the intrusion of the operator in the conversation circuit, at the armature 845 it opens the circuit of relay 830 which therefore releases. When the busy local line becomes free again, relay 870 releases as before and the called subscriber receives inrush current as described previously.

   When the called subscriber answers he accepts the communication which is transferred to him in the manner which was explained above.



   CLAIMS.



   ---------------------------- 1. A telephone system comprising a local office provided with certain facilities which enable local subscribers to receive and take local communications and in connection with the public network in which each privileged subscriber is provided with a key with an unstable position, when the subscriber is engaged in a communication in connection with the public network and he activates this key he blocks the incoming trunk line and can get in touch with a second local subscriber who, by activating the push-button on his set, can connect to the incoming trunk line, the connection between the first subscriber and this trunk being released.

** ATTENTION ** end of DESC field can contain start of CLMS **.


    

Claims (1)

2. A telephone system comprising a local office provided with certain facilities which allow local subscribers to take and receive local calls and <Desc / Clms Page number 60> in connection with the public network in which any local subscriber can answer a call coming from the remote office by sending one or more determined digits, which are the same for all local subscribers, and which set the switches, normally used for local communications, positioned on a particular level to control the connection between the incoming junction and the line of the responding subscriber, following a path independent of the local selection train. 3. A telephone system comprising a local office provided with certain facilities which allow local subscribers to take and receive local calls and in connection with the public network in which a local subscriber can receive a communication from a public office in bringing the local selection train into a particular position which extends a marking, characteristic of the line of the subscriber who answers, to the terminals of a specific finder at the incoming junction which searches for the line of the subscriber and connects it directly to the trunk, the answering subscriber being able to connect to the line of a second local subscriber, while maintaining the link to the remote office, using a selection train separate from the local office. 4. A telephone system comprising a local office provided with certain facilities which allow local subscribers to take and receive local calls and in connection with the network of two remote offices in which each line to these offices is provided. for service in both directions and terminates at the local office at a finder who has access to all local lines, the operation of the researchers being controlled by sending a digit to the local subscriber's station. <Desc / Clms Page number 61> forming part of a group of 9 determined digits, the first used to initiate the connection with the line of the subscriber of the researcher associated with the junction on which a communication arrives from any of the two offices, the second and third serving to cause the connection of the subscriber's line and of a free trunk to one or other of the remote offices respectively, to allow the subscriber to take a call to either of these offices. 5. A telephone system using two-movement final selectors having access to lines with two grouped stations and provided to ring these selectively according to the conversation wire to which the inrush current is applied, in which, when one of the telephones must be rung the first movement of the selector is carried out in two steps; at the end of the first step, as a result of the closing of circuits which are established without the seoours of the selector brushes, the appropriate talk wire is chosen and the selector talk circuits are modified so that the second step of the selector movement brings the selector to the position it reaches in one step when the number of the other extension grouped on the same line is sent. 6. A telephone system as claimed in claim 1, 2, 3 or in which the local office includes an operator position from which calls from a remote office can be answered, the signaling devices at each subscriber station then being disconnected and a signal specific to the operator and planned for its position being put into service. 7. A telephone system as claimed in claim 3 in which the transfer of a call to a second local subscriber station is effected by releasing the finder <Desc / Clms Page number 62> and putting it back in position on the line of the second subscriber, the connection between the subscriber who answered and the second subscriber being released thereby. 8. A telephone system as claimed in claim 2 in which the transmission by the local subscriber, of one or more determined digits, is used to put the switches in a different position to establish the connection of the subscriber's line to an outgoing junction to the office remote, by a channel independent of the local seleotion train and which includes a searcher specific to the outgoing junction, which allows the local subscriber to take a call to the remote network. 9. A telephone system as claimed in claim 4 or 8 in which the connection established through the local switches causes the operation of a distributor which selects a finder and sets it in motion. 10. A telephone system as claimed in claim 9 in which the subsequent functioning of the researchers is controlled by a tag which comes from the distributor, and ends up passing through the local selection train / to the researcher bench. 11. A telephone system as claimed in claim 10 wherein the finder scope is of the two movement type and in which group and line markings extend to the vertical and horizontal test contacts, respectively. 12. A telephone system as claimed in claim 9 in which the distributor cannot be entered until the searcher has found the local line. 13. A telephone system as claimed in claim 1 or 3 in which the control exercised by the local subscriber <Desc / Clms Page number 63> to block the connection to the junction is carried out by the actuation of an unstable key which causes the disconnection of the junction line of the conversation wires leading to the local subscriber's station and the connection of a blocking bridge between the wires of the junction. 14. A telephone system as claimed in claim 1 or 3 in which the connection to the second local subscriber is established by means of a finder having access to all the incoming junction and a connector which is associated with it and has access to all the local lines. 15. A telephone system as claimed in claim 14 in which the seeker searches for the junction in service and connects it to the subscriber line which responds by means of a searcher specific to the junction. 16. A telephone system as claimed in claim 14 in which the connector is connected to the second local line under the control of the pulses emitted by the subscriber who answers. 17. A telephone system as claimed in claim 2 or 4 in which when transferring a communication with the remote office to the second local subscriber, the searcher associated with the junction releases and is returned to position to make a direct connection with the line of this subscriber. 18. A telephone system as claimed in claim 17 in which the return to position of the finder is controlled by a distributor which is activated when the pushbutton of the station of the second local subscriber is actuated and which extends the group and line markings through the connector to the terminals of the researcher associated with the junction. 19. A telephone system as claimed in claim 18 in which the finder associated with the junction is <Desc / Clms Page number 64> provided with separate test circuits, one of which becomes operative when responding to the communication with the remote office and the other when transferring a communication with the public network. 20. A telephone system as claimed in claim 2 or S in which the local office also includes a stopper position provided with facilities enabling it, if it takes a call to a local subscriber, when a junction is blocked, to maintain this connection until the subscriber local has hung up, at this time communication between the attendant position and the local subscriber is immediately established. 21. A telephone system as claimed in claim 20 in which the operator can also enter a local call in progress by causing the transmission of a special tone on the line of the subscriber called to let him know that it is requested for another call. 22. A telephone system in principle as described and shown in the attached plans.