Patent GB-188138-A (GB)
Abstract: 188,138. Western Electric Co., Ltd., (Western Electric Co., Inc.). Sept. 13, 1921. Automatic and semi-automatic exchange systems.-In a system in which calls arriving at a manual exchange from an automatic exchange are stored in register-sets and thence transferred in turn to a number indicator, means are provided for marking all the inter-exchange trunks busy when all the register-sets hold waiting calls. In the system illustrated two register-sets are provided, one of which is shown in full in Fig. 3 and comprises the registers 510 - - 540, sequence switch 450 and trunk-finder 431 - - 434. The other set comprises registers 510<1> - - 540<1>, sequence switch 490 and trunk-finder 531. The registers operate the lamp indicator in the 16th position of the corresponding sequence switch, and the switch is advanced to its 1st position as soon as the operator completes the indicated connection. The switches 420, 490 are prevented from both standing in the 16th position at the same time. If both switches 410, 490 are in positions intermediate between the 1st and 16th, i.e. if calls are being stored in both register sets, contacts 486, 496 open a circuit 441, Fig. 2, common to the group of trunks from the automatic exchange, de-energizing a relay 406, Fig. 1, at that exchange, which drives a sequence switch 400 to its 4th, 10th or 16th position. The movements of the switch 400 are repeated over contacts 407. 408 to a second switch 410. The test circuits of all idle trunks of the group are now opened at contracts such as 401, 424 so as to render them unseizable by the selectors. On re-energization of the relay 406 the switches 400, 410 are advanced to their 1st, 7th or 13th position to render idle trunks again available. The registers 510 - - 540 are set by a reverting-impulse system of control to positions complementary to those of registers 110 - - 140, Fig. 4, of a register controller at the automatic exchange, which is designed for the control of selectors on a non-decimal basis. The operations in setting up a connection to the manual exchange are as follows. Call finders; selection of idle register-controller. A calling line is extended by first and second call finders in known manner to an idle group selector and the sequence switch 220 moves to its 4th position, energizing relay 235 and closing a circuit 214, 210, 281 for the switch 280. When this switch reaches a position corresponding to an idle register controller, relays 234, 323 are energized in a circuit 281, 234, 243, 282, 310, 323. Relay 234 locks itself through its low-resistance left-hand winding in series with relay 232, which open-circuits the switch 280 and drives the switch 220 to its 5th position, connecting the calling line over contacts 221, 223, 313, 314 to relay 325 of the register-controller. Relay 323 drives the switch 32C to its 3rd position, by a circuit through its own left-hand winding, and then relapses, its original circuit being open at contact 310. Contact 315 completes a circuit for giving dialling tone to the calling subscriber. Setting of register controller. Under control of the relay 325 and of a differential relay 329, the digits dialled by the calling subscriber successively set the registers 100 - - 140 as described in Specification 146,517. The last interruption of each digit series is prolonged to energize a sluggish relay 334, which controls relay 323 to drive the switch 320 to successive positions, until eventually, when all the registers have been set, the switch 320 moves to its 15th position. Group selector. As soon as the first digit has been registered the switch 320 moves to its 6th position, closing a circuit 353, 351 to drive the switch 350 to its 3rd position, in which the relays 355, 222 are energized in a fundamental circuit 354, 355, 283, 242, 222. The relay 222 drives the switch 220 to its 6th position to energize the clutch magnet 248 of the brush tripping spindle. The fundamental circuit is intermittently grounded by contacts 250 to short-circuit relay 355, which advances the register 100 by closing a circuit 356, 359, 342, 120, 100. On the next de-energization of relay 355 after the register 100 has regained its normal position a circuit 356, 359, 342, 102, 341, 350 is closed to drive the switch 350 to its 4th position and to energize relay 357, which opens the fundamental circuit. Relay 222 is thus de-energized to open-circuit the magnet 248 and to drive switch 220 to its 7th position, whereupon relay 222 is again energized in a circuit 243, 282, 329 and energizes magnet 241 to rotate the brush carriage. The selected brushes are moved over the terminals of the trunks to the manual exchange. When an idle trunk is reached, relays 234, 403 are energized in a circuit 402, 401, 403, 253, 228, 234, 210, 281. Relay 234 locks itself through its low-resistance left-hand winding in series with relay 232, which de-energizes magnet 241 and drives the switch 220 to its 9th position. Operation of trunk-finder, Fig. 3, to connect register-set to calling trunk. Relay 403 locks itself in the test circuit independently of contact 401, and closes a circuit 411 to energize relay 414, which energizes relay 415, 416, 418, 419. Relay 416 shunts out the high-resistance left-hand winding of relay 414 so as to energize a marginal relay 404, which locks itself in the circuit 411. Relay 418 closes a circuit 474 for the driving magnet 461 of the trunk-finder 431 - - 434, assuming this switch and its register-set to be idle. When the wiper 434 reaches the terminal of the calling trunk, relay 464 is energized and locks itself through its low-resistance left-hand winding in series with relay 462, which open-circuits the magnet 461 and drives the switch 450 to its 4th position. Relays 462, 464 are now disconnected from the test wiper 434 and are energized over wiper 432 in series with relays 426, 427. Relay 426 energizes relay 421, which de-energizes relay 418. Transfer of records from registers 110 - - 140, Fig. 4, at automatic exchange, to registers 510 - - 540, Fig. 3, at manual exchange. When the switch 320 leaves its 6th position, after the second digit has terminated, a circuit 353, 351 is closed to drive the switch 350 to its 6th position, energizing relays 452, Fig. 3, and 355, Fig. 4, in a fundamental circuit 459, 452, 431, 423, 413, 242, 283, 355, 358, 297, 284, 255, 412. Relay 452 drives the switch 450 to its 5th position closing a circuit 510, 521, 468 to drive the register 510. The fundamental circuit is intermittently grounded at contact 513 to short-circuit the relay 355 to advance the register 110 by a circuit 356, 359, 343, 111. When the register 110 regains its normal position a circuit 356, 359, 343, 111, 342, 102, 341, 350 is closed to drive the switch 350 to its 7th position, and relay 357 is energized to open the fundamental circuit. Relay 452 is thus da-energized, open-circuiting the register 510 (which is thus brought to rest in a position complementary to that in which the register 110 was set) and driving the switch 450 to its 6th position. Similarly when the dialling of the third digit is completed the switch 350 moves to its 9th position, the fundamental circuit is again completed and the register 120 transfers its record to the register 520, and thereafter the registers 130, 140 in turn transfer their records to the registers 530, 540, after which the switch 350 moves to its 16th and the switch 450 to its 14th position. Release of register-controller. Contact 329 opens the circuit 293 of relay 222, which drives the switch 220 to its 10th position, whence it is driven again over contact 217 to its 11th position. The calling line is now disconnected from the register-controller at contacts 221, 223 and extended to the trunk 412, 413. The relapse of relay 325 causes the restoration of switches 320, 350 to normal. Transfer of wanted number from registers 510 - - 540 to lamp indicator; translating arrangements. If the lamp indicator is idle, i.e. if the switch 490 of the second register-set is in any but its 16th position, a circuit 493, 456 is closed to drive the switch 450 to its 16th position, in which lighting circuits for the indicator lamps are closed through contacts of the registers 510 - - 540. The registers 110 - - 140 are arranged for a non-decimal selector system and therefore record the wanted number in a non-decimal form on the registers 510 - - 540. Arrangements are therefore provided between the registers 510 - - 540 and the lamp indicator for re-translating the number to its original decimal form. Thus if the register 110 is set to an odd position a relay 360 is energized so that during the setting of register 510 register 110 is restored only to its 9th position, being driven an extra step to its normal position during the subsequent setting of the register 520. Thus the register 520 is given one extra step and the register 510 one step minus. This is compensated by the contact 524 of the register 520, which selects one or other of a pair of thousands lamps accordingly as it is set in an odd or even position. Again. if the register 120 is set to an odd position relays 373, 374 are energized, with the result that the register 540 is run through an extra cycle in the course of its control by register 140. This is compensated by arranging that the register 540 at the commencement of its second cycle energizes a relay 561, which selects an odd instead of an even hundreds lamp. Call signal; release of lamp indicator and register-set. In the 16th position of the switch 450, the circuit of relays 462, 464 is transferred from wiper 432 to wiper 433, so that relay 426, Fig. 2, is de-energized and lights a call lamp 442. The operator answers by inserting the plug 443 in the jacket of the indicated subscriber, energizing relays 428, 420. Relay 428 bridges the trunk 412, 413 to energize relay 262, Fig. 1, which drives the switch 220 to its 12th (talking) position.