Patent GB-200537-A (GB)
Abstract: 200,537. Western Electric Co., Ltd., (Western Electric Co., Inc.). Feb. 7, 1922. Automatic exchange systems; coin-freed systems.-In a coin-freed system in which connections are established by means of a register-controller set by impulses from the calling subscriber, the register-controller is provided with auxiliary mechanism which controls the substation coin device at all stages of the connection both during its establishment and after the initiation of the release. For this purpose, the register-controller employed in establishing the connection is reeased in the usual manner as soon as the connection is completed but, when the calling subscriber hangs up, a register-controller is again temporarily associated with the connection to control the collection or refund of the coin. The same auxiliary mechanism also controls the refund of the coin in the case of a prematurely-abandoned call. If a call is abandoned at any time before the dialling of the third digit, the associated register-controller effects the refund of the coin, but if abandoned after dialling the third digit, a complete connection is established, the final selector being set to a " telltale '' position, and the re-connection of a register-controller and the refund of the coin take place in the same way as in the case of a completely-dialled unsuccessful call. In the system described, a subscriber A, Fig. 1, desiring to call a subscriber B, Fig. 3, whose designation is, say, LIS 9532, is connected over a preliminary selector 100 to a district selector 250, Fig. 2, provided with a switch SF which hunts for an idle register-controller, Figs. 4 and 5. The selected register-controller is set in known manner in accordance with the dialled impulses, the first three code digits being translated so as to control the selector 250 in its selection of an idle two-wire trunk 306, 307 leading to the wanted exchange, the remaining digits controlling the completion of the connection over an incoming selector 300 and a final selector 350. The selectors 250, 300, 350 are of the power-driven panel type controlled by reverting-impulses and may, for example, be of the type described in Specification 24928/13. The special mechanism associated with the register-controller comprises two step-by-step time-measuring switches TM, M each having six wipers and associated contact banks, the switches being stepped round through complete cycles by their magnets 502, 418 respectively, under the control partly of independently-driven interrupters and partly of their own self-interrupting contacts. Certain definite timeintervals are thus marked off during which certain operations such as the commencement of dialling, the deposit of the coin, the completion of the connection, &c., should have been effected. The switch M serves for monitoring purposes, lamp signals being given to an exchange attendant in case of (1). failure to commence dialling within a given time, (2) failure to complete dialling, (3) failure to deposit a coin or jamming of the coin, (4) a faulty register-controller which fails to complete the connection, and (5) faulty collection of the coin due to jamming. The arrangements at the register-controller are such that units selection cannot take place until a coin has been deposited. The system also provides for the operation of a meter, in cases where the calling-subscriber's line is so equipped. Prelimirary selector, Fig. 1. When the calling-subscriber removes his receiver, relay 101 completes a circuit, for stepping magnet 105 which rotates the wipers 108 - - 113 from the first or normal set of terminals, over the second set in which the test terminal is permanently grounded to the third set at which hunting commences. When a free trunk, as denoted by a battery connection to lead 114, is reached, relay 102 energizes in series with the left-hand winding of relay 101, locks itself in series with relay 226, Fig. 2, over lead 118 and switches through to leads 117, 116. An off-normal contact 123 grounds the calling-subscriber's test terminal 121 in the banks of final-selector switches, and a second off-normal contact 124 prepares a restoring circuit for the switch 100. Operation of register-selecting switch SF and setting of registers. Relay 226, energizing over lead 118, directly grounds lead 114 to mark the selected trunk busy, thereby de-energizing relay 101, and energizes relay 228 over contacts 204, 205 to drive the sequence, switch 200 into its 2nd position in which a slow-release differential relay 227 energizes over contact 205 and locks up relay 226. Stepping-magnet 229 energizes in a circuit 208, 207 over a front contact of relay 228 which remains locked over contacts 210, 211 to the test wiper 231 as long as this wiper is resting on the grounded test terminal of a busy register-controller. The wipers of the switch SF are stepped forward until an idle register-controller is reached, when relay 228 falls back. driving the switch 200 into its 3rd position and relays 230, 244 energize in series with magnet 229 which is no longer energized. Relay 230 energizes differential relav 501, Fig. 5, which completes a circuit for the stepping-magnet 502 of the timemeasure switch TM over wiper 503 and interrupter 504. The switch TM is stepped from its normal (or zero) position to its 2nd position, thereby allowing a suitable time interval before relay 505 operates to connect the calling subscriber to the registering mechanism. As soon as the switch leaves its normal position, the register-controller is marked busy to other switches SF by grounding the test lead 500 over the right-hand winding of relay 501 and off-normal bank 511. In the 2nd position of switch TM, relay 505 energizes over wiper 507, locks up, and completes a circuit over wiper 508 in which magnet 502 energizes and steps the switch TM into its 6th position. Relay 505 also closes the impulsing circuit 512, 513, 403, 236, 116. S. 117, 232, 402, 404, 516 in which relay 512 energizes and closes the circuit of a slow-release relay 517. The monitoring timemeasure switch M, Fig. 4, is also brought into operation by relay 501 which completes a circuit over wiper 406 for the starting-relay 405. A slow-release relay 409 energizes over the circuit 411, 477, 499 and closes circuits for relays 410, 416. Stepping - magnet 418 energizes over its interrupter contacts and wiper 417 to step the switch M into its 1st position in which relay 410 de-energizes and magnet 418 is connected in series with slow interrupter 419 over wiper 477 under the influence of which, after a short. time interval, the switch M reaches its 3rd position. If the calling subscriber has not dialled the first digit within this time interval, the switch M waits in this position and a monitoring lamp 421 lit over wiper 423 and an auxiliary pilot lamp 424 over wiper 477 give a signal to a monitoring attendant. When the calling subscriber dials the first digit, relay 512 repeats the impulses over a slow-release relay 519 and a lead 521 to the first code register. Stepping-magnet 522 of switch RS remains energized during the set of impulses but de-energizes at the end of the digit and moves forward the switch RS one step from its normal for zero) position, the second set of impulses being repeated over relay 519 and wiper 520 to the next code register. In a similar manner the remaining impulses are repeated to the other registers, the switch RS moving forward one step at the end of each digit. In the 1st position of the switch RS, relay 410 energizes over the circuit 417, 426, 523 and the magnet 418 steps the switch M into its 5th position in which relay 410 de-energizes and magnet 418 is connected in series with interrupter 419 and wiper 477 to step the switch to its 7th position. If, during this time interval, the subscriber has not completed his dialling operations, lamp 421 glows dimly in series with a resistance 427, lamp 424 lights as before and the monitoring operator is notified. Operation of district selector 250 under control of registers. When switch RS reaches its 2nd position, relay 525 energizes over wiper 523 and, in known manner, initiates the translation of the code set up on the code registers and causes the sequence switch 527 to move into its 2nd position in which a fundamental circuit 228, 210, 237, 530, 534 is completed. Relay 228 energizes in this circuit, locks up over contact 210 and the fundamental circuit, and drives the switch 200 into its 4th position in which the up-drive magnet 238 is energized to raise the shaft 239 for the brush-selecting operation. During the upward movement, the fundamental circuit is intermittently grounded over the brush 241 and commutator strip 242, the relay 530 transmitting impulses to a relay-counting-chain 0, 1 - - 9, 9<1> set in known manner in accordance with the translated first digit. When the proper number of impulses has been sent back, relay O<1> energizes to drive the switch 527 into its 4th position and relay 532 opens the fundamental circuit, unlocking relay 228 which falls back and drives the switch 200 into its 5th position. When the switch 527 moved from its 2nd position, the operated relays 0, 0<1> &c. were released and the fundamental circuit again closed. Relay 228 energizes, locks itself to the fundamental circuit as before and drives the switch 200 into its 6th position, in which group selection takes place in a similar manner under the control of brush 248 and strip 249. When, at the end of this operation, relay 532 opens the fundamental circuit, the switch 527 moves into its 6th position, and relay 228 de-energizes and drives the switch 200 into its 7th position, in which relav 228 energizes and the switch 200 moves to its 8th position, in which trunk-hunting takes place. Relav 228 remains locked up over contacts 216, 224 and the grounded test brush 252 as long as