Patent GB-321454-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04M3/32
Filed: 1928-08-10
Abstract: 321,454. Automatic Telephone Manufacturing Co., Ltd., and Pearce, O. A. Aug. 10, 1928. Automatic and semi-automatic exchange systems.-In an automatic routine tester, the maximum time occupied by each of a number of portions of the test is determined by a stepping switch which is driven by timed pulses and controls alarm circuits. The invention is described in connection with the routining of B-operator's sending equipments. If a sender is busy when it is seized by the routiner, the stepping switch FTS continues its motion until the sender becomes idle and is then restored to normal, but if the sender remains busy for an abnormal time, the switch FTS reaches its last contacts and an alarm is given. A test number is transmitted to the sender, and the digits sent back to the routiner are displayed on the panel shown in Fig. 1, an alarm being given if an incorrect digit is received. Alarm circuits are also completed (1) if the routiner does not receive the full number of digits by the time FTS has advanced to its 9th contacts, and (2) if the sender, after the transmission of the digits, does not release itself before FTS has advanced to its 13th contacts. A further timing switch PT tests the pauses between digits Preliminary operations; test for busy sender. The test operator sets up the test number, assumed to be 2345 on the key-set shown in Fig. 2 which indicates only the connections of the keys FNK, LNK for the first and last digits, and the start key 14, Fig. 7, is operated to connect ground over 15 to relay HO, Fig. 6, which operates HOR, Fig. 4. The start key also completes circuits over 26 and 29 respectively for slow-to-operate relay BE and magnet DM5 of the primary distributor PD, the circuit for the magnet being opened by BE so that PD steps on to terminals associated with the first sender distributor SD. The lamps shown in Fig. 7 indicate the sender under test and are connected up in turn over wipers 233, 230 of SD and PD. Relay BJ, Fig. 6, is also operated over wiper 33 of PD. Relay BE energizes BA, Fig. 10, and should SD be resting on contacts of a busy sender, ground on busy conductor 39, Fig. 5, is connected over wipers 40, 41 of SD and PD to relay BB, Fig. 8, which opens the circuit of BC and completes a stepping circuit for the test switch FTS, Fig. 9. The stepping circuit includes contact 48 of impulsing relay IP which is intermittently operated by earth pulses over conductor 50, Fig. 6. The first application of ground at 48 after the operation of BB partially energizes relay PG which pulls up its light armature 53 and fully operates at the end of the pulse so that the next operation of IP completes the circuit of DM7, Fig. 9, which steps the test switch FTS in synchronism with IP. If the sender remains busy, FTS steps on to its last contacts and completes a circuit from ground at key 60 over key 61 for relay AL, Fig. 10, which locks up, opens the circuit of DM7, and closes a circuit from ground at 68 for lamp 71, Fig. 9, and the lower winding of alarm relay X, Fig. 6. Relay X locks over its upper winding and keys 61, 60 to ground at key 14, and at 75 completes a circuit for local alarm bell 76 which may be extended by key 77 to operate a further alarm. The operator momentarily depresses re-start key 60 to restore the circuits to normal. If the sender becomes available before FTS reaches its last contacts, the removal of ground from conductor 39 releases relay BB which opens the stepping circuit of FTS and completes circuits for relays BC, IS which extend ground from 86 to conductor 39 in order to busy the sender to its normal means of access. The release of BB also completes a homing circuit for FTS and when this switch reaches its first contacts, a circuit from ground at key 60 over key 61 and wiper 63 is completed for start relay ST, Fig. 8, which locks up and sets in operation a relay impulse group for stepping the pulse sender PSS. Sending the test number 2345. The relay impulse group comprises relays BM, AM, SA, Fig. 10. Relay BM is operated by ST and energizes AM which releases BM to close a circuit for SA which reoperates BM and falls back so that pulses are sent from 106 over 107 to magnet DM9 of the sender PSS. When the sender arrives at its second contacts, ground over key 2 is connected over wiper 10 of PSS, wiper 112 and second contact of PD. and wiper 113 and first contact of SD to conductor 114 and thence to the thousands storage relay group of the sender under test, which, after registration, transfers the connections to the hundreds storage group. When PSS reaches position 4, ground over key 3 of the second set of digit keys (not shown) is connected over wipers 10 and 11 of PSS and wipers of PD and SD to the hundreds storage relays. The remaining digits are similarly registered in positions 6 and 8 of PSS and when this switch reaches position 11, ground at the sender under test returned over conductor 115, Fig. 5, is connected over wipers 116 of SD and 117 of PD to the upper winding of CO, Fig. 6, which locks over its lower winding to the busy conductor 39, and at 121 completes a circuit from ground at 147, Fig. 3, for relay SI this ground also being extended over 123, Fig. 8, wiper 125 of PD and wiper 126 of SD to conductor 127 which is connected to the relay which starts the sending operations at the sender. Relay SI, at 81, releases relay IS, Fig. 10, so that the ground from 86 connected to the busy conductor 39 is removed, a circuit (130, Fig. 4, 90, 91, Fig. 9, 93, 56, Fig. 6, 58, Fig. 10) being closed for magnet DM7 of the test switch which moves to position 2 to test whether ground has been returned from the sender. If ground is not returned, CO does not hold so that IS releases, and as SI has already fallen back, a circuit is completed from ground at key 60 over wiper 63 of FTS, 132, 133, Fig. 4, 135, Fig. 8, for relay AL which locks up and completes a circuit for lamp 136<1>, Fig. 9, including relay X which, as previously described, prepares alarm circuits and at 136, connects ground from key 14 to conductor 39 to busy the sender until the fault has been rectified. The switch PSS has in the meantime reached position 15 and relay SE, Fig. 10, energizes over wiper 139 to ground at 35, Fig. 8, locks up and disables the relay impulsing group BM, AM, SA, a homing circuit for PSS being completed at contact 107 of AM. Checking the number sent out by the sender. As previously mentioned, the operation of CD initiated sending operations and energized SI, Fig. 4. Relay A is now bridged across the normally looped impulsing leads at the sender by way of the distributors PD, SD, and conductors 114, 152. Relay A connects ground over conductor 62 to relay B so that at each relapse of A this ground is connected over relay C to magnet DM1 of minor switch NR1, Fig. 1 which registers the first digit. Relay C operates and energizes D during the impulse train at the conclusion of which C falls back and completes a circuit for KA (upper), Fig. 3, which partially operates to complete a circuit over 161 to ground at 128, Fig. 6, for both windings in series when D releases. Relay KA transfers the impulsing circuit to minor switch NR2 and connects ground from 164 over the lamp 170 corresponding to the setting of NR1, conductor 167, key 2 of FNK and resistance 169 to battery. If an incorrect digit is received, ground from 164 is connected over an incorrect lamp and cable 167 to an unoperated key and thence over common conductor 171 to relay XR which connects the grounded conductor 74 to a " wrong number " lamp 174 and to the alarm relay X. The digits are repeated in turn to the switches NR2, NR3, NR4 and checked, and when relay KD operates on the completion of the last impulse train, ground from 147 is connected over lamp 178, multiple cable 176, key 5 of LNK, conductor 177 to relay Y (upper). In the meantime, the test switch has been stepped on to position 9 in a circuit from contacts 48 of continuously impulsing relay IP over 51, 179, 93, 56, 58, and if the full complement of impulses from the sender has not been received, relay Y is not operated so that ground at key 60 on conductor 62 is extended over wiper 63 and 180, 181, 182 to relay AL which lights lamp 136<1> and initiates the alarm as before. Testing pause between digits by switch PT, Fig. 9. This test is described only in respect of the pause between the first and second digits but may be applied to pauses between all the digits. When NR1 comes to rest after taking two steps in the case under consideration, intermittent ground over 200, 201, 202, key 2, 203, 204, Fig. 10, to PS (lower) which partially operates at 206 and locks to the grounded conductor 162 at the end of the first pulse. The pulses are now transmitted over 204 to magnet DM8 of PT. As soon as the impulses of the second digit come in from the sender, a branch of the stepping circuit for DM2, Fig. 1, from grounded conductor 62 over 146, 156, Fig. 4, extends over 214, 209, and wiper 216 of PT to relay PL which locks over its upper winding and opens the stepping circuit of PT. If the pause has been short, ground from 220 over wiper 222 lights lamp 223 and operates alarm relay X, while if too long, lamp 224 lights up instead of 223, the test being stopped by relay X in either case. Switch PT returns to normal after completion of the test on the sender, when the removal of ground from conductor 162 releases PS which at 207 completes the homing circuit of the switch. Completion of test on sender; release of registering and indicating equipment at the routiner, and subsequent operation of distributors. When the sender has completed its operations, a cut-off relay energized to effect its release, is held over conductor 127, Fig. 5, to ground at 147, Fig. 1, and connects ground to busy conductor 39 to maintain CO. When, however, relay KD operates after the reception of the last digit, it removes the ground at 147 to release the cut-