Patent GB-257967-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/00
Filed: 1925-04-08
Abstract: 257,967. Western Electric Co., Ltd., (Western Electric Co., Inc.). April 8, 1925. Automatic exchange systems.-In a system of the register-controller type the registers and controllers are separate organisms and are temporarily associated during the setting up of a connection. The controllers transmit sets of impulses not only for the numerical operations but also for setting group selectors on the first idle trunk of a wanted group. The invention is illustrated in its application to the control of a group selector 200 and connector 250 of Strowger type, only the control of the group selector being described in detail. A three-digit register is shown in Figs. 3 and 4 and is connected to a groupselector controller, Figs. 5 and 6, over a channel 500 common to other registers and controllers. Impulse transmitting circuits in the controller are connected over a channel 600 to the selector 200, and a set of test relays 660 individual to the value of the first digit is connected over a channel 650 to the test circuits 225 &c. of the wanted group of trunks. By means of a counting chain 510 the controller first sends a series of impulses representing the hundreds digit to the vertical magnet 206 of the selector 200, and then, by co-operation of the same counting chain with the test relays 660, sends to the rotary magnet 207 as many impulses as are necessary to set the selector on the first idle trunk of the selected level. Registration of dialled number. A calling line 101 having been connected by cross-bar switches 100, 130 to a group selector 200 and to a register, Figs. 3 and 4, a circuit (not shown) is closed for relay 105 which energizes relay 107 and switches the calling line to relay 301, which energizes relay 304, which energizes 307 and closes a circuit 321 322, 140 to lock 105. At the first impulse dialled, the relapse of relay 301 removes a shortcircuit from relay 308, which energizes a self-locking relay 306 and a relay 309 ( which locks itself over a circuit 324, ( 326 in series with the first relay 312 of a 6-relay counting chain. The relay 312 is short-circuited by relay 308 until the termination of the impulse, but ( then becomes energized, locks itself, ( end transfers the circuit 324 to relay 313, the momentary opening of the circuit during the movement of the armature being sufficient to de-energize refay 309, which is quick to release on account of a self-closed opposing winding. The second impulse locks up the relay 313 which unlocks 312, and so on. As long as impulses continue the relay 307 is kept energized by relay 308, but at the termination of the digit it relapses and closes circuit 328 to energize relay 407, which connects the four relays of the hundreds register 400 to the wires 330, 331, &c., so that a combination of these relays is energized corresponding to the digit. Relay 408 is thereby energized and opens a shunt round relay 305 which becomes energized in series with 407 over circuit 426 and de-energizes 306 which de-energizes 305, 407. The second and third digits are received in the same way and recorded on the registers 402, 403. Connection of register to controller and of controller to group selector over channels 500, 600, 650. Relay 408, as soon as the first digit is recorded, closes circuit 333 to energize relay 310, which closes circuit 334 to energize relay 509, which energizes relays 506, 512, 503, 515, 516. Relays 503, 516 connect the register, Figs. 3 and 4, to the controller, Figs. 5 and 6, over the common channel 500 and close a circuit 524 to energize relay 601. This relay closes circuit 636, 590 through contacts of the hundreds register 400 and over the top four wires of the channel 500 to copy the record of the register 400 on to a group of four relays 520 - - 526. A branch circuit say 527, is then closed to energize relay 602, which energizes relays 606, 610. Relay 606 closes circuit 643, 519, 340, 142, 144 to energize relay 205, which energizes relay 612, and relay 610 energizes relay 611. The connections over the channels 500, 600, 650 are now completed. The left-hand test relays 624, 622, &c. are connected to the test circuits 225, 223, &c., and those relays which correspond to busy trunks become energized. Tha relay 612 is individual to the selector 200. The relays 602, 606, 610, 611 and the test chain 660 are individual to the value of the hundreds digit. For a different value of this digit, similar but different relays would be energized and a different testchain would be taken into use. Control of group selector. Relay 613 is energized over the two bottom wires of the channel 650 and closes a circuit for the right-hand test relay, say 625, corresponding to the first idle trunk of the wanted group, thereby preparing a circuit from an interrupter 614 (shown separately in Figs. 5 and 6) over wires 532, 626, 627 to a point in the counting chain 510 corresponding to the value of the hundreds digit. For a different value of this digit a different test chain would be taken into use and the circuit 627 therefrom would lead to a different point in the counting chain. The relay 613 also connects the interrupter 614 to relay 616, which locks in series with relay 617, which is energized at the next interruption and completes the above impulse circuit to the counting chain, at the same time closing an impulse circuit 614, 531, 618, 619 to the vertical magnet 206 of the selector. The counting chain builds up to the left, a pair at each impulse, until relay 533 is energized, which unlocks all the chain relays except 533, 534 and energizes relay 530 to transfer the interrupter circuits to control the rotary movement of the selector, The interrupter 614 is now connected, on the one hand over circuit 535, 633 to the rotary magnet 207, and on the other hand over circuit 536, 634 to a point in the counting chain corresponding to the energized test relay 625 of the first idle trunk. As soon as the chain is built up so far as to energize relay 542 a circuit is closed to energize relay 208, which locks itself to the circuit 116 and de energizes relay 205 to disconnect the group selector from the controller. During the vertical and rotary movements, relays 214, 218 are energized and energize, selflocking relays 190, 143. Release of group-selector controller. The energization of relay 208 closes a circuit 116. 223, 225 to energize relay 640, which closes a circuit 641, 544 to energize relay 311, which locks itself and opens the circuit 334 of relay 509 to release the channel 500. This de-energizes relay 601 which unlocks all energized relays in the controller and in the channels 600, 650. Control of connector. The energization of relay 420, as soon as the final digit has been recorded, closes a circuit 428, 343 to energize relay 425, which closes a circuit 439, 344, 146, 147 to the a-wire of the connector to energize a relay similar to 205 to couple the connector with circuits leading to a controller. Relay 420 also closes circuit 428, 345 to energize a relay similar to 509 to connect the register with a controller (not shown). Release of register. After the connector has been set, relay 342 is energized over circuit 346 and energizes relay 303, which locks itself and de-energizes relays 301, 304, whereby all energized relays in the register are released and relay 105 is de-energized to switch the calling line through and to unlock relays 143, 190. Release of connection. During conversation relay 107 is kept energized by relay 106. The relapse of relay 107 de-energizes relay 208 which closes the circuit of the release magnet 228.