Patent GB-194313-A (GB)
Abstract: 194,313. Western Electric Co., Ltd., (Assignees of Jacobsen, E.). March 3, 1922, [Convention date]. Automatic and semi-automatic exchange systems.-In systems in which digits delivered from an automatic to a manual exchange are displayed on a number-indicator, a single indicator and several register-sets being provided at each operator's position, a lamp is flashed before the operator if impulses arrive in a connecting circuit before the latter has been associated with an idle register-set. In the system described, all idle incoming trunks are connected by associated preselective switches to the same idle register-set, and the record stored in a register-set is transferred to the indicator when the operator presses an assignment key. Operation of tne register-set. The line relay 207 energizes a slow-release relay 212, which closes a circuit for relays 216, 217 in series with the stepping magnet 215 of the hunting switch, this circuit being of too high resistance, however, to energize the magnet 215. The relay 216 grounds the wiper 241, to energize the magnets 215 of idle trunks to cause the associated hunting switches to move forward to the terminals of the next idle register-set, and closes a circuit 301, 324, 322 to drive a switch 364 to its 2nd position. The impulses are repeated by the line relay 207 over a circuit 239, 304, 335, 327 to the first register magnet 333, which steps the arms 348, 392, 340. At the termination of the first digit the slow-release series relay 335 relapses and drives the switch 364 to its 3rd position, so that the next digit is repeated to the second register magnet 346, and so on. After the last digit has been registered the switch 364 moves to its 6th position, energizing relay 337, which locks itself and lights a lamp 263. Transfer of number to indicator. When the operator is ready to deal with the call, she presses a cord key 265 to energize relay 264, which locks itself and connects the lamp 263 to an interrupter to give a flicker signal identifying the proper cord with the number that is about to be displayed. The relay 264 also closes a circuit 273 for relays 371, 374 and energizes relays 213, 269, which lock up and de-energize relay 212. The relay 371 completes the circuits of the selected indicator lamps, and relay 374 drives the switch 364 from its 6th to its 11th position. Release of register-set and indicator. When the operator inserts the plug 278 a sleeve relay 267 unlocks relay 264 which de-energizes relays 371, 374, and a relay 388 becomes energized and closes circuits for the register magnets 333, 346, &c. over the arms 348, 350, &c. to restore the registers. When all the registers have regained their normal positions a circuit 395, 394, &c. is completed to drive the switch 364 to its 1st position, whereupon all the relays in the register-set are de-energized and also relays 216, 217, which have hitherto remained locked in the circuit 301, 329. Supply of ringing current. Supervisory signals. Meanwhile a relay 283 energized by relay 267 has completed the ringing circuit through a marginal relay 285, which is energized when the called subscriber replies and removes a shortcircuit from relay 284, which becomes energized and short-circuits relay 283, which relapses and completes the talking circuit. When the calling subscriber disconnects himself, relay 207 falls back and short-circuits relay 269, which unlocks relay 213, and a lamp 280, being no longer shunted by relay 284, lights up as a signal that the connection should be taken down. Signalling the arrival of impulses when no register-set is ready to receive them. If the trunk 128, 129 is seized while the hunting switches are searching for an idle register-set, the relays 216, 217 are not energized, being shortcircuited through the test-wiper 241, and if an impulse arrives while this state of things endures, a relay 281 is energized and energizes relay 213, which completes an interrupter circuit 232 to flash the lamp 280 to warn the operator, who may transfer the call to a trouble operator. The Specification as open to inspection under Sect. 91 (3) (a) describes also a second system, shown in Fig. 4 (Cancelled) and Fig. 5 (Cancelled), in which a calling trunk is connected by relays to an idle register-set, the register-sets being taken into use in strict rotation, and the transfer to the indicator being effected by a chain of relays, so that as soon as a call has been dealt with by the operator a waiting call is automatically displayed. Each trunk has three relays 412, 413, 414 for connecting it to the three register-sets. Three relays 417, 418, 419 individual to the register-sets determine the order in which they are taken into use. This subjectmatter, which does not appear in the Specification as accepted, is described in the following paragraphs. Selection of idle register-set. The relay 405, energized by the line relay 402, energizes relay 416, which connects the relays 412, 413, &c. to circuits 426, 427, &c., one of which, corresponding to the next idle register-set, is connected to battery over contacts of relays 417, 418, &c. Assuming that relay 412 becomes energized in this way over circuit 426, it connects the trunk to the first register-set and locks itself in series with the corresponding relay 417, which also locks itself independently through its left-hand winding and transfers battery trom circuit 426 to 427. The next call is therefore dealt with by the second register-set and causes the energization of relay 418, and the next subsequent call is dealt with by the third register-set, even if the first register-set has meanwhile become idle, and causes the energization of relay 419. The energization of this relay completes a chain circuit for relay 420, which opens the locking circuits through the lefthand windings of relays 417, 418, 419, so that if the first or the first and second register-sets have meanwhile passed out of use, the corresponding relays 417, 418 relapse and enable them to be taken into use again. Operation of the register-set. The impulses are repeated by relay 402 over wire 422 to relay 504, which repeats them to the register magnets 502, 503. Only two of the registers are shown. At the termination of each digit a slow-release series relay such as 506 transfers the impulse circuit to the next register. Transfer of number to indicator. The three register-sets are connected to the indicator 523 - - 526 by the energization of corresponding relays 508, 509, 510. On the termination of the final digit the relapse of the series relay 507 prepares a circuit for the lower winding of relay 508, this circuit being at once completed, if the indicator is disengaged, through back contacts of the relays 508, 509, 510. If, however, either the second or third register-set is at this moment coupled to the indicator, the corresponding relay 509 or 510 prevents the relay 508 from becoming energized until the indicator is set free. The relay 508 completes the lamp circuits selected by the registers and locks itself over the wire 423 in series with relay 406. Release of register-set and indicator. When the operator plugs up the wanted connection, the sleeve relay 407 de-energizes relay 412 to release the register-set, and the relapse of relay 505 closes restoring circuits for the registers.