Patent GB-288723-A (GB)
Title: Improvements in telephone systems
IPC: H04M3/32
Filed: 1927-01-13
Abstract: 288,723. Automatic Telephone Manufacturing Co., Ltd., and Simpson, L. M. Jan. 13, 1927. Automatic and semi-automatic exchange systems. - Routine testing equipment is described for use in testing register-translators of the type described in Specification 233,007, which are accessible to subscribers over " A " digit switches, and the general lay out is somewhat similar to that shown in Specification 267,606, which relates to routing testine equipment for operators' key-sending positions. All the registertranslators in the exchange are normally tested in succession, but if desired, the test may be applied only to the register-translators of a particular group, or to a particular register-translator. Sets of keys are provided for setting up the input, test number and the expected output number, and the number is sent into the registertranslator twice under conditions which represent the extreme working limits of operation. Special arrangements are made for including the tenth group of register-translators which are used in completing calls to operators in the general routine test. The effects of releasing and reversing the out-impulse wires to the register-translators are tested. General routine test. This is initiated by operation of the general routine key GRK and start key SK. The group distributor GD is advanced one step under control of relay 17 to make connection with the first register-translator accessible over the distributor RD1. Relay 30 energizes over wiper 351, and relays 1, 10, 28 are connected up, while relay 63 energizes over wipers 357, 366. If the register-translator is busy, ground on the test wire 373 energizes relay 6, which disconnects relay 10 and causes the lighting of a lamp 557 if the busy condition continues for a certain time. If the next registertranslator is busy, relay 26 energizes over the corresponding test wire and disconnects relay 28 until the register-translator becomes free, whereupon it is guarded against seizure by a subscriber. Relay 10 connects up relay 249 to advance the control switch CS one step, and extends the outimpulse wires 371, 372 to the windings of relay 465. The forced-release test is initiated by the energization of relay 151, which connects up relay 576 to complete the circuit of relay 465, connects the in-impulse wire 374 to relay 253 and a suitable interrupter to relay 255. When the registertranslator releases, battery is connected to wire 374 and relay 253 energizes and advances the switch CS one step. If the register-translator fails to release in a given time, relays 255, 217 energize and lamp 267 is lighted. Relay 601 now energizes in place of relay 151 and connects an impulse-machine to the magnet 404 of the release relay timing switch BS. Relay 576 falls back when ground is removed from the test wire 373, and disconnects relay 601. Relay 598 energizes and lights the appropriate lamp 407, 408 or 409, according as the time is too short, correct or too long. The switch CS advances, and relay 160 energizes, connecting up relays 576, 193, and the latter connects an impulse machine to the magnet 403 of the sending switch SS. The input and output keys are set, the exchange designation being one which produces the same translation in all the groups of register-translators. When the switch SS moves off-normal, relay 197 energizes and removes a short-circuit from a synchronous impulse machine 276, which is connected to the in-impulse wire 374 through a series resistance 270. Impulses are sent until the terminal in the bank of the switch SS marked in the first keyset is reached, when relay 201 energizes, again short-circuiting the impulse machine 276, stopping and restoring the switch SS, and advancing the switch CS. Relays 197, 201 are disconnected in the normal position of the switch SS, and the second exchange digit is sent to the register-translator. Further input digits are then delayed until the first translated digit is received back, this being effected by the operation of relay 593, which acts similarly to relay 151 and controls relays 255, 217 to light a lamp 269 if the first digit is not received within a given time. The impulses from the register-translator are received by relay 465, which repeats the first set to the magnet 481 of the first minor switch, and switching relay 475 is energized at the end of the train due to the relapse in turn of relays 470, 472, lighting the appropriate indicating lamp and connecting up the next minor switch. If the digit is incorrect, relay 609 energizes in series with the lamp and lights lamp 560 in addition. An interrupter is connected first to relay 182 which unlocks relay 201 to renew the sending operation, and then to the magnet 555 of the pause timing switch PT. When the first impulse of the second train is received, relay 177 entergizes, stopping the switch PT and lighting the lamp 558 or 559 if the pause is incorrect. Switching relay 486 on energization causes relay 208 to pull up, reversing the connections of relay 465 to the out-impulse wires 371, 372 : this should energize a polarized relay in the register-translator to hold up further sending. Relay 166 energizes after an interval, and disconnects relay 208 and sending is now resumed. If any impulses are received from the register-translator while the wires 371, 372 are reversed, relay 222 energizes, lighting a lamp 268 and preventing advance of the switch CS. When all the digits have been sent, the switch CS is in the 10th position, and relay 593 energizes, but relay 193 is disconnected to prevent sending of any further impulses. Relay 160 is dependent on the switching relay 500 of the last minor switch, so that it relapses when all the digits are received back, and removes ground from the test wire 373. Relay 616 energizes in series with the last indicating lamp and effects the restoration of the minor switches. The switch CS advances one step, and relay 242 energizes, connecting up faster impulse machines, replacing the series resistance 270 in the in-impulse wire 374 by a shunt resistance 271, and re-energizing relay 160. The sending operation is now repeated under the fresh conditions. In the 18th position of the switch CS, relay 15 energizes and relays 1, 10, 249 are disconnected, releasing the registertranslator. The magnet 367 receives an impulse and the distributor RD1 connects up the next register-translator, which is subjected to the same series of tests. In the 25th position of the distributor RD1, relay 35 energizes in series with relay 63, and when relay 15 energizes after the tests have been completed, the magnet 359 receives an impulse to advance the group distributor GD into engagement with the next distributor. Testing of the tenth group. This contains those register-translators which give access either to a toll operator or to a monitoring operator according to the class of the calling subscriber, who dials only the digit O. Actually certain of the regular register-translators are employed for this purpose., with their out-impulsing wires reversed, consequently the forced-release test is not necessary. On seizure of the appropriate distributor RD 14 (represented only by wiper 360), relays 66, 71, 226, 233, 208 energize, and relay 249 is disconnected to prevent the sending of impulses. Relay 233 changes the circuits of the indicating lamps as in Fig. 7, which are now such that no alarm is given if the correct digits are received irrespective of the setting of the output keys. The minor switches not required are cut out by relay 71. Relay 208 reverses the connections of relay 465 of the out-impulse wires, and relay 576 energizes. If the correct routing number, e.g. 216, is received, relay 616 energizes and advances the distributor RD 14. In the case of the register-translators giving access to a monitoring operator, relay 41 also energizes, and substitutes relay 238 for relay 233 to change the circuits of the indicating lamps. When all the register-translators have been tested, the group distributor GD advances a step, and relay 24 energizes, disconnecting relay 17, lighting a lamp 129<1> and energizing alarm relay 170. The attendant restores the keys SK, GRK, and the group distributor GD and RD 14 are returned to normal. If the start key SK is restored while a test is in progress, the relapse of relay 17 effects the same restoring operation, and any other switches which are off-normal are also restored. Any spare terminals in the banks of the test wipers of the distributors and multiplied to relay 37, which controls an interrupter circuit for advancing the distributor over the spare positions. Testing of a particular group of register-translators. The group key, e.g. MN, is operated instead of the key GRK. At the first step of the group distributor GD, no circuit is closed for relay 30, and an interrupter circuit is completed for operating the magnet 359 until the desired group is reached, when relay 30 energizes. After all the register-translators of the group have been tested, the group distributor is returned to normal in the same manner. Testing of a particular register-translator. The keys CK, GK are operated to step the group distributor and the appropriate distributor into engagement therewith. The test is repeated until stopped by the attendant. The reversed line sending test is made if the key GRK is operated after selection. Modified tests. The keys FRK, SEK, SHK are provided for omitting the forced release test and the series and shunt sending tests if desired. For tests involving a code only, e.g. INF for " information," the keys CEK, CHK are provided, allowing respectively the series and shunt sending of two digits only to the register-translator. Faults. In the case of a non-standard condition being encountered, relays 170, 612 serve to connect up the main alarm through relay 562 and to mark the faulty register-translator busy. The attendant