Patent GB-264680-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04M3/32
Filed: 1925-08-24
Abstract: 264,680. Automatic Telephone Manufacturing Co., Ltd., (Automatic Electric Co.). Aug. 24, 1925. Automatic exchange systems. - Testing- apparatus for register-controllers is automatically associated with each register-controller of a group in turn to apply a particular test thereto. When each register-controller has successfully passed this test a different test is automatically applied to each in turn and further similar tests may take place in rotation. If any register-controller fails to operate properly in response to any particular test, the sequence of operations is interrupted and the particular register-controller and the nature of its fault are indicated to an attendant. If a register-controller when selected by the testing-apparatus is busy in setting up a call, the apparatus waits until the setting operations are completed and then applies the test. The testing-apparatus passes by, without testing, a register-controller which an attendant has marked permanently busy. Means are provided by which if desired any particular test may be applied repeatedly to a single register-controller or the whole series of tests may be applied to a single register-controller. The apparatus shown in the drawings, which should be arranged as shown in Fig. 11, comprises a hunting-switch, Fig. 2, which selects the register-controllers in succession, an impulse-sending arrangement, Fig. 3, for transmitting impulses to the register-controller under the control of counting relays, Fig. 5, and further counting relays, Fig. 7, for receiving the digits sent back. A selecting switch, Fig. 4, automatically determines which of the several tests is being applied, relays such as 601, Fig. 6, selected by this switch controlling by means of two distributing frames SIDF, RIDF, both the number sent out by the impulse sender and the operation of the test circuits for the received number. The particular tests described are as follows :-(A) The number 431 is transmitted to the register-controller and the number 3431 should be sent back. This is illustrated in Fig. 6. (B) A test similar to A but with a different number. (C) The number 111 is sent out and after the same digits 111 have been sent back the same operations are repeated to test whether the apparatus in the register-controller has properly released after the first setting. (D) The timed-release feature of the register-controllers is tested. For this test, Fig. 10 should replace Fig. 6. The impulse-sending apparatus, Fig. 3, may be tested as to speed and impulse ratio of the impulses by the means described in Specification 241,512. Test A (of registering, translating and impulsesending operations); seizure of first registercontroller. To start the testing operations, the attendant operates key 419 to cause the test selector, Fig. 4, to advance its wipers to select the first test, thus operaing relays 601, 602, Fig. 6. She also operates key 324 to start the self-interrupting relay 301 which intermittently operates marginal relay 303. Relay 602 completes a start circuit or relay 204 which causes relay 201 to operate over wiper 223 in series with relay 806 in the first register-controller, Fig. 1. Relay 201 marks the register-controller busy to the normal register selectors and connects up relay 205 which operates and energizes relay 206, this in turn operating relay 304. Transmission of test number (431) to registercontroller. At the next de- .energization of relay 303, earth is connected over the circuit .614, 245, 327,340 to relay 500 which, on the succeeding energization of relay 303, locks in series with relay 501. Relays 500, 501 ensure that the first impulse sent out will be a complete one. Relay 501 energizes relay 306 which removes a short-circuit from springs 325 of relay 301, so that on the next release of relay 301, an impulse is transmitted to relay 304 which in turn transmits a.n impulse over contacts 532, 328, 220, 702 to the first register magnet 909 of the register controller. The subsequent release of relay 303 operates relay 502 which then locks in series with relay 503. After four impulses, the operation of relay 509 completes a circuit 571, 613, 544, for relays 305, 526 in parallel. Relay 305 prevents further impulsing and releases the counting chain 500 - - 509, the opening of contact 544 causing relay 527 to energize in series with relay 526 in preparation for the second digit. The next two digits are sent in a similar manner and at the end of the third digit, relay 523 completes a circuit 571, 565, 610 for relay 307 which locks up, removes earth to prevent further impulsing and releases the digitccntrol relays 522 - - 527. Transmission of corresponding number from register-controller. Impulses are sent out by relay 811, Fig. 1, to relay 205 which repeats them over the circuit 260, 248 to the relav chain 712 - - 722, and in parallel to relay 207 which remains energized during a digit and completes a circuit for relay. If the first digit sent out by the registercontroller is correct (three impulses), relays 703, 714 are energized and the relapse of relay 207 at the end of the digit completes a circuit for relays 210, 211 in series, the latter however being short-circuited over contacts 730,733, 617, 822, 616. Relay 210 operates to release relay 209 and the operated relays, Fig. 7, and the next digit is received and tested in a similar manner, the digit-control relay 805 having operated over contacts 821, 617, 733, 255. 614 and locked in series with relay 801. If a wrong first digit is sent out, the short-circuit for relay 211 is not completed, relay 210 which is marginal does not operate but relay 211 energizes, puts resistance earth at armature 259 on the pulse lead to the register-controller to prevent the latter from releasing, sounds an alarm 412 and lights lamp 1, Fig. 8, to indicate that the first digit is wrong and lamp 4, Fig. 7, to indicate that the digit 4, say, has been sent out instead of the digit 3. A lamp connected over wiper 222, Fig. 2, indicates which register-controller is faulty, whilst the lamp in parallel with relays 601, 602 indicates which test is being applied. The attendant may repair the fault and then operate key 261 to release relay 209 and all the operated relays. the same test being then repeated from the beginning. Key 241 is opened to prevent the selection of the next register-controller. If all the digits sent out are correct, relay 210 operates at the end of the operations over the circuit 616, 822, 834, SW, 328, 259, 220 to earth sent forward from the register-controller, releasing relay 209 and completing a circuit for relay 208. Relays 204, 203, 201 and the registercontroller are released and the stepping magnet 212 is energized over contacts 922, 241, 240 to connect up the next register-controller to which the same test is then applied. Register-controller busy. If a register-controller is reached which is engaged in setting up a call, earth on the test wire energizes relay 202 which lights a busy lamp, this lamp remaining lit until the register-controller becomes free when the test already described takes place. A register-controller may be marked permanently busy so as to be passed over by the selector 220 - - 225 by throwing a busy key, Fig. 1. Test B. When test A described above has been applied to all the register-controllers, wipers 220 - - 225 move to their last contacts where wiper 225 completes a circuit for magnet 212 in series with relay 403. The latter operates and energizes magnet 404 of the test selector, Fig. 4, which in turn connects direct earth to operate magnet 212. On the release of magnets 212, 404, wipers 220 - - 225 move to the first register-controller whilst wipers 410, 411 move to their next terminals which are connected to cause either the repetition of the first test or the. initiation of a different test. As shown the terminals are so connected that the test A is. repeated six times, test B eight times, test C five times and test D once. Test B differs only from test A in that a different number is sent into the register-controller. Test C. In order to test that the digit registers will release properly under all conditions, the testing mechanism sends the number 111 and after this number has been sent back from the registercontroller, the same test is repeated on the same registercontroller so that if release has been faulty after the first test, this will become apparent during the second test. The operation is similar to that already described with the exception that in order to prevent wipers 220 - - 225 stepping on after the first test, the circuit of magnet 212 is held open at contacts 922 by a relay (not shown), the first connection of earth over contacts 243, 236, 241 operating a further relay which subsequently bridges contacts 922 so that the second connection of earth over these contacts will cause magnet 212 to operate. Test D (of timed-release feature). The register-controller, if not operated by further digits after it has commenced to send out, is controlled by a timing-mechanism to release the associated switches in the talking circuit by opening the loop and then to again seize the first selector and route the call to an operator. In testing this feature, the test sender transmits only two digits 99 and the register sends out a single digit 9 followed after an interval by a digit 1 for routing the call normally to an operator. When wiper 411 reaches the fourth set of contacts in its bank, relays 1001, 1009, Fig. 10, are operated and the lead to relay 204 is earthed, but the start lead to the impulse sender, Fig. 3, is not closed until the timing-cam TP, Fig. 2, operates relay 1002. Sending operations then take place as already described and after the digit 9 has been sent back, relays 1014, 1008 are operated. At the next closure of cam TP, earth is extended over contact 1050 to relay 1013 which operat