Patent GB-326248-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/00
Filed: 1928-12-10
Abstract: 326,248. Automatic Telephone Manufacturing' Co., Ltd., and Taylor, R. Dec. 10, 1928. Automatic exchange systems. - A register-controller at a step-by-step exchange for dealing with traffic incoming from a revertive control exchange arranged on a different numerical basis, transmits to the revertive control exchange, and simultaneously records, a series of trains of impulses to saturate the register at the revertive control exchange, and, after translation of the record, transmits a further series of impulse trains to operate the step-by-step switches. In one system described, subscribers at the revertive control exchange are allotted five-digit numbers (first digit 3), and are reached over alternate levels of first group selectors R1, Fig. 9, second group selectors R2 and 200-point final selectors R3. The subscribers at step-bystep exchanges are allotted four-digit numbers (first digit 3 excluded) and are reached over the remaining levels of R1. The incoming group selectors at the step-by-step exchange have two sets of wipers and the final selectors are ordinary 100-point Strowger switches. When the relay group JRD (Fig. 2) at the incoming end of the junction is seized, an idle register controller RC (Figs. 4 and 6) allotted by distributor JFD (Fig. 8) is connected up over finder JF. In a modified system for a 10000-line step-by-step exchange, this exchange is reached over one level of the first group selector at the revertive control exchange, and the step-by-step switches are arranged strictly on a decimal basis. In the registercontroller, Figs. 4 and 6, translation is effected by cross connections between banks of the registers DR and a bank of the sender SS controls the transmission of impulses to the step-by-step switches, the register being associated with the sender in turn by a relay chain DA - - DD which has also served to distribute to the registers the impulse trains corresponding to the revertive impulse trains. In the modified system referred to above, the sending of the translated impulse trains may commence before complete registration of the reverting impulses. Seizure of register-controller at step-by-step exchange. The first group selector (wipers 17, 18, Fig. 1) at the revertive control exchange has a selected junction 19, 20 terminating in a relay group, Fig. 2, at the step-by-step exchange and a circuit is completed from ground at 70 over L1, L, 44, stepping relay OSR in the fundamental circuit of register-controller RG, to battery over 72. Relay OSR does not now operate, but LZ pulls up, marks the junction in the banks of JF by removal of ground at 33, and energizes start relay FS, Fig. 5, which completes a circuit for relav FK and magnet 78 in series. If JF is standing on terminals of a busy or non- calling junction, ground over 33 or 36 and wiper 466 short-circuits FK and completes a self-interrupting circuit for 78. When JF fails to pick up ground over 466, FK pulls up and magnet 78 closes to operate. Relay FK locks up over contact 362 of busy guard relay BG which was energized by FS, connects up the leads to the register-controller, Figs. 4 and 6, and at 390 completes a circuit for magnet 414 of the finder distributor JFD over contacts of idle register controller corresponding to 340, 384. Relay FS falls back shortly after the operation of FK, but relay BG, being slow to release, will be held as described later. Relay TK of the junction group operates over SK, 465, 396, 362, 348, relay SK remaining unoperated, and at 51, 45 completes a circuit from ground at 70, over the fundamental circuit in RCS, 464, 398, 207 for relay RC which at 180 completes its circuit independently of 207, connects the two-step relay PA to ground over impulse springs 327, and at 182 completes a holding circuit for BG (upper) to ground on conductor 306. Relay TK also releases L and LZ and busies the junction at 35. Relay PA pulls up in two steps and locks to ground on 306, transfers the impulse circuit to IM, and connects ground from 306 over 196 to two-step relay DB which closes its contacts 262. Transfer of record from register-controller RG to the registers at the step-by-step exchange. Relay IM repeats impulses at 184 to magnet 450 of register DR100 in series with low resistance relay BP which operates intermittently without effect, and at the same time the register in RG is counted out by reverting impulses from 188 which short-circuit the stepping relay OSR but hold RC. Relay IC operates during the impulse train. When the fundamental circuit is opened in RG, RC relapses, opens the impulse circuit, and releases PA which permits DB to energize fully and transfer the impulse circuit to magnet 452 of DR10. The circuit of IC is also opened, but, before it falls back, PG operates over 209, 308, 464, 20 to battery over 21 in RG, locks over 175, and at 171 closes a holding circuit for BG (lower) which, since the relapse of RC, has been held over 205 of IC. After IC has fallen back and PG has released owing to the re-making of the fundamental in RG, the remaining digits are registered in DR10, DRU, relay DC being energized after registration of the tens digit to transfer the impulsing circuit to the units register, and relay DB falling back. When the units digit has been registered, DD pulls up in a similar manner to DC and DB, releases DC, prepares the outstepping circuits, and at 231 completes a circuit for TK and SK in series independently of resistance 395 so that SK operates, disconnects wiper 464 from conductor 20 and sends back tone over 61. At the revertive control exchange, the register-controller is released and the junction is connected over 10, 11 to the feed relays B, C, Fig. 1. Line relay L, Fig. 2, now energizes over both windings in series with retard L1, and release relay B1 pulls up locks, completes a circuit in the left-hand winding of D1, and at 70 removes ground from conductor 19, relay L being now held by ground over C, Fig. 1. Relay B1 connects ground from 68 to wiper 463 to hold the guard relay PG which is now solely dependent on B1 and FK. Transmission of impulses to the step-by-step selectors. The energization of DD after the registration of the units digit connects the impulse springs 327 to relay PA which pulls up in two steps, over 198, 278, 400, 463, 68, and transfers the impulse circuit to the back-stroke magnet 456 of sender SS. DA (upper) is energized and operates its contacts 270. At the end of the first impulse, SA operates over 468 and removes the short circuit 284 about the impulse springs 328 which are out of phase with 327 and therefore closed. Impulses are thus sent over 312, 313 to the incoming selector and from 327 to the sender until wiper 469 of SS reaches the terminal marked by wiper 462 of DR100. Relay SZ pulls up over these wipers and locks over 276, 282 to ground on 306, short-circuits springs 328, opens the impulse circuit of magnet 456, and at 274 completes a homing circuit for SS. Relays SA, SZ relapse. It will be seen that when SZ is operated, it releases PA so that DA operated fully and transferred ground over 306 to wiper 464 of DR10. The tens and units digits are sent to the connector in a similar manner, relay DB being fully operated at the and of the tens digit to transfer ground over 306 to wiper 467 of the register DRV. Relay DC fully operates at the end of the units digit,. Translating arrangements at the step-by-step exchange. (1) Thousands digit odd. The selectors at the revertive control exchange are such that the pairs of hundreds digits 2 and 3, 4 and 5, &c. require an even number of reverting impulses to saturate the register at the revertivecontrol exchange so that DR100 stands on odd terminals and wiper-selecting relay OS of the incoming step-by-step selector operates over 81, 460, 402, 311, 461, 246, 190, 202, 211 to ground on 306 immediately prior to the registration of the tens digit on DR10. Relay OS locks over its lower winding. The number of reverting impulses for the units digit indicates whether the hundreds digit is even or odd, more than ten impulses being required if it is odd. If this is the case, DR100 is given an extra step, immediately after the setting of DRV, in a circuit over relay BP, 301, 450, second half of the bank of 466, 199 to ground on 306, this circuit being opened when IC falls back after DRV is set. The digits of each hundreds pair are thus separated out and the connections between the banks of wipers 462, 469 are such that SS sends the impulses for the hundreds digit corresponding to those originally dialled. (2) Thousand-digit even. The pairs of hundreds digit are, in this case, represented by odd numbers of reverting impulses so that DR100 stands on an even terminal and relay OS is not operated. The number of reverting impulses for any pair is one less than that of the corresponding pair when the thousands digit is odd, consequently, DR100 must be given an extra step. Immediately prior to the setting of DR10, relays DB and PA being operated, DR100 is stepped in a circuit BP, 301, 450, 461, 246, 190, 202. 211 to ground on 306, this circuit being opened when IC operates. If the hundreds digit is odd, DR100 is given a further step as described above. The tens digit does not require compensation in any case but the terminals of 464 are connected to those of 469 in reverse order. In the case of the units digit, the connections between 467 and 469 are also in reverse order and the wipers of DRU stand on the first or second halves of its banks according to whether the hundreds digit is even or odd, but it will be seen from the bank of 467 that this does not effect the digit sent by SS. Release of register-controller. After the units digit has been transmitted, DB, DC. DD are all operated so that RR energizes over its upper and locks over its lower winding, removes ground from conductor 306 to release BC, DC, DD, and also FK which disconnects the register-controller. Relay BG falls