Patent GB-248891-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/42
Filed: 1925-01-31
Abstract: 248,891. Automatic Telephone Manufacturing Co., Ltd., and Ostline, J. E. Jan. 31, 1925. Automatic exchange systems.-If the impulse springs in a register controller are faulty, it is released and marked busy and an alarm is given as the result of a testing operation which takes place automatically as soon as it is seized. This release occurs at the end of the first digit received. For routine testing a key is provided which connects the outgoing to the incoming impulsing wires and arranges for a predetermined digit to be sent to all the register magnets in succession. The invention is described with reference to a register controller similar to that described in Specification 233,007. Automatic test of impulse springs. The register controller is seized over the wire P, and relay A energizes relay B over 11, 10. Relay B grounds the release wire PR, starts the motor for driving the springs MPS, LPS over M5, and partially energizes a two-step relay LC over LPS, 16, 10. When the springs LPS open, relay LC pulls up all its armatures, connects LPS to the outgoing loop +L. -L, and partially energizes relay CC over 23, MPS, 74, 3 (of SC) 80, 81, 27, 29, 16, 10. When the springs MPS open, relay CC is fully energized over 30, 74, &c. Relay A repeats the first digit to the vertical magnet V of the office register OR in a circuit 31, 33, C, 34, 3 (of DD). Series relay C on pulling up energizes relay N over 35, 27, and on falling back energizes the driving magnet R<1> of the sequence switch DD over 38, 37, 35. Relay CC on pulling up energizes the driving magnet DM<1> and causes the switch SC to move off normal, but if either set of springs fails to operate, relay PA pulls up in a circuit 44, 4 (of SC), 82, 84, 2 (of DD), 27. Relay PA locks up, completes an alarm circuit PFA, grounds the release wire PR over 49, 46, 50, connects intermittent ground from IE to the lamp SL and the relay TP, the latter circuit being over 47, 53, 55. Relay TP is energized partially in this circuit and at the end of the ground period pulls up all its armatures, and energizes relay M over IE, 47, 52. Relay M puts battery on the incoming impulse wire, P to release the register controller, whereupon all the relays but PA fall back. The latter is released by the key BK when the fault is cleared. Routine test. The attendant inserts momentarily a plug into the jack T to close the contacts 61 - - 64. Relay A pulls up and is followed by relays B, LC, CC as described in the preceding paragraph. Relay RT pulls up over 63, 65, N<1>, 66, 10, locks itself direct to 10, grounds the release wire PR in place of contact 64, and the ninth terminal in the bank 2 of the sending switch SS, locks up relay A over 70, D, 73, 69, and connects the sending switch magnet DM to the springs MPS over 23, MPS, 74, 3 (of SC), 75, 76, 77. At the first step, relay S pulls up over 1 (of SS), 85, 86, 80, 81, 27, shortcircuits relay D, unlocks relay A, and connects it to the springs LPS over 70, 73, LPS, 69. Relay A repeats the impulses to the vertical magnet V as described above. When the sending switch reaches its ninth terminals, stop relay T completes a restoring circuit for the sending switch. Nine impulses are sent in a similar manner to the remaining register magnets, after which relay RT is released by a short-circuit over 27, DD(2), 92, and releases the register controller. If any of the switches do not release, relay RA gives an alarm. If the plug is left in jack T the test is repeated indefinitely. The Provisional Specification describes in detail an arrangement the functions of which axe the same as those of the apparatus described above, but the circuits of which though similar are not identical. The principal difference appears to be that the alarm relay corresponding to PA is energized over a back contact of the two-step relay corresponding to CC and is independent of the switch SC. The energizing and locking circuits of the relay corresponding to CC differ also.