Patent GB-292691-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04M3/32
Filed: 1927-03-25
Abstract: 292,691. Automatic Telephone Manufacturing Co., Ltd., and Ostline, J. E. March 25, 1927. Semi-automatic exchange systems.-Relates to routine testing apparatus for direct CCI repeaters including means for sending impulses to the coder and receiving the resulting code impulses sent from the coder and for testing each leg of the outgoing junction separately. The testing apparatus is associated with the repeaters in turn by primary and secondary distributor switches, the particular repeater under test being indicated by group lamps controlled by the. primary distributors and individual lamps common to the secondary distributors. The various tests take place in different positions of a sequence switch which stops when a repeater fails to pass the test and indicates the nature of the fault by means of lamps. A delayed alarm is given when the sequence switch stops and, if desired, when any of the switches stick off normal. Means are provided for controlling the distributors to select a particular repeater, for re-starting the test without clearing a fault and for testing the same repeater repeatedly. Keys are provided for simulating faults to enable the operation of the tester to be checked. Specifications 229,371 and 233,007 are referred to. The Provisional Specification describes a similar arrangement which however performs fewer tests and does not test the legs of the junction separately. Repeater, Fig. 1. Line relay A on pulling up starts the hunting switch in search of an idle coder, and when one is found, relay K reverses the connections of the line relay to signal the register controller to send the next digit. When the coded number has been sent, relay CZ connects relay H across the outgoing junction (relay HA having been energized when the repeater was seized) and releases the coder and when the operator plugs in, relav H cuts off the line relay, completes a metallic circuit back to the first code selector, and locks itself to the c-wire. The wires 37 - - 42 are led to the correspondingly numbered banks in a secondary distributor such as SD, Fig. 4. Distributing arrangements. Operation of the start key 10, Fig. 4, energises relays S, SS, Fig. 9, and connects an intermittently grounded wire 46, Fig. 8, to relay DR, Fig. 9, which at the first impulse energizes relay DA in two steps and at the second a sluggish relay TC, a two step relay DB and the back-stroke driving magnet DM3 of the first secondary distributor SD. Relay DB disconnects relays DR, DA, TC and locks up over a back contact of relav TO which is energized at the end of the test cycle. The relapse of relay DB then allows a further impulse to be sent to magnet DM3. The terminals in bank 42 corresponding to blank positions are grounded, and this ground energizes relay KA, Fig. 7, which releases relay DB to allow a further impulse to be sent to magnet DM3. When the last repeater connected to switch SD has been tested, relay TO, in addition to releasing relay DB, energizes relay TS over bank 43 of switch SD. Relay TS locks up and causes the second operation of relay DR to energize the back-stroke magnet DM1 of the six right-hand wipers of the primary distributor PD1. When these wipers move on, a circuit is made over 81, 103 for magnet DM2 of the left-hand wipers. With relay TS energized, the second impulse operates the two-step relay DC, instead of relay DB, whereupon relay TS falls back and the third impulse operates relay DB and the magnet of the new secondary distributor. Ground connections are made to the blank positions in bank 475, the circuit thus made holding relay TS to allow a further impulse to go to magnet DM1. When switch PD1 reaches its final terminals it extends the test leads to switch PD2 and energizes a relay DX, Fig. 9, to transfer the stepping circuit. In a similar manner relay DY transfer the stepping circuit to the magnet of switch PD3. If it is desired to test one repeater continuously, the key 20 is thrown to energize relay CR, Fig. 5, which opens the driving circuits of the distributors and the circuit of relay TS. To re-start the test on the next repeater if it has been stopped by a fault, key 47 is thrown to disconnect the impulse wire from relay DR and energize KA which releases relay DB and energizes relay K which locks up over a back contact of relay DB and releases relay KA. A homing circuit is thus made for the sequence switch, and on the restoration of the key 47, an impulse is sent to the magnet DM3, or if necessary to magnet DM1 and the magnet of the next secondary distributor, relay TO being energized in this case over a contact of relay K. If it is necessary to test a particular repeater, the start key is restored and the distributors go home. Key 20 is then thrown to operate the start relays S, SS and the relay CR and keys 14, 15 are operated to send impulses to the driving magnets of primary and secondary distributors in turn. If the repeater required is reached over the switch PD2, the key 19 is thrown to energize relays DX, SA which switch over the impulsing and test circuits to that switch. In a similar manner key 18 is thrown to operate relays DX, DY, SB if the repeater is reached over the switch PD3. Seizing repeater for test. When relay DB pulls up and the switch SD moves on to the terminals of the repeater to be tested, relay RS, Fig. 7, pulls up and ground is connected to wiper 87 of the sequence switch. Relay RS over 119 and wiper 120 in its first position energizes magnet DM4 which opens its own circuit and moves the sequence switch into its 2nd position. Relay TA, energized by the momentary energization of relay TC, disconnects the 2nd terminal on bank 120 and locks itself over 128, 131, 132, 41 to the release wire of the repeater, if the same is busy. If not or when it becomes idle relay TA falls back and marks the repeater busy over the last mentioned circuit 135, 24, 10, operating relay HA in the repeater. Relay TA also restores the ground connection to the 2nd terminal in bank 120 to drive the sequence switch to its 3rd position. Testing outgoing junction. Relay TD, Fig. 7, energized over wiper 87 in position 3, connects high resistance relay TE over 145, 39 to the upper wire of the junction. Relay TE pulls up in series with the distant line relay (which does not) and connects a high resistance relay TR, Fig. 5, over 152, 40 to the other wire. Relay TR over 120 drives the sequence switch to its 4th position. Testing adjustment of repeater impulse relay and selection of coder. In position 4, wiper 87 energizes relay NOT which energizes relay TJ. The latter locks up, connects polarized relay LP across the outgoing leads from the repeater and over 221, 224, 225, 42 short circuits relay HA to disconnect the outgoing junction. At the same time the impulse relay A is bridged by resistance 169 in series with relays TL, TF, in a circuit 37, 159, 160, 163, 171, 175, 38. Resistance 169 is such that relay A ought not to operate. Relay TF pulls up, cutting off relay SR to allow impulse wire 46 to be connected to the magnet DM4 which then drives the sequence switch to its 6th position in which relay NOT falls back and opens the driving circuit. If through wrong adjustment, relay A does pull up, a coder is selected and the relay K pulls up, reversing the connections of the line relay and causing relay TF to fall back and energize relay SR which stops the sequence switch (in 5 or 6), and locks itself up. Assuming, however, that relay A correctly fails to pull up, the relapse of relay NOT in position 6 energizes magnet DM4 over wiper 120 and the switch moves to its 7th position, in which wiper 87 energizes relays TH, X in parallel, the latter locking both relays to ground at 126 and connecting the impulse wire 46 to magnet DM4. Relay TH grounds the 10th terminal in bank 120 and connects relays TF, TL and resistance 192 in series across the leads to the impulse relay A. Relay A should now pull up and cause the selection of a coder, whereupon relay TF which partly energized a relay TM, falls back in response to the current reversal and allows relay TM to pull up completely and ground terminals 7 - - 9 in the bank 120. Relay TM also substitutes the impulsing contact 166 of relay A<1>, Fig. 5, for the circuit TL, TF, 192, and cuts off relays X, TH, the latter remaining up long enough to ensure that the sequence switch moves to its 11th terminals. If, through faulty working, relay TF fails to fall back, relay SR pulls up over the 9th terminals and wiper 87, locks itself and stops the sequence switch. Transmitting 11111 to coder.-First method. In position 11, wiper 87 energizes relay TN which locks itself up and energizes relay C which energizes the weak winding of two step relay D in parallel with relay A<1>, the latter causing relay A to fall back and send an impulse into the coder. Relay A' energizes relay CO and relay B which releases relay A1 to terminate the impulse, allows relay D to pull up all its armatures, and locks itself up. Relay CO locks itself under control of relay B and releases relay C which releases relay B. Relays C, B, CO therefore fall back in succession, whereupon relay C again energizes relay A1 and an impulse is sent as before, the two step relay E taking the place of relav D. Relays F - - H operate in succession at the end of each digit in the same way as relays E, D, relay H over 120 driving the sequence switch to 12. Transmitting 11111 to coder-2nd method. Fig. 5 is replaced by Fig. 10. Wiper 87 in position 11 connects ground over 199 and springs 411 to relay LC which pulls up in two steps and connects the impulse springs to relay A1 which at the next impulse energizes relay SC in two steps. At this nstant armature 416 is back and armature 415 is up and the loop to the epeater is thus opened and relay A sends an mpulse to the coder. At he same time relay D is partially energized over back contact 417 of relay A1. When relay A1 pulls up again to co