Patent GB-411456-A (GB)
Title: Improvements relating to automatic telephone systems
IPC: H04Q3/42
Filed: 1932-12-06
Abstract: 411,456. Automatic exchange systems. SIEMENS BROS. & CO., Ltd., Caxton House, Tothill Street, London, LONG, D. P., 3, Ingleby Way, Chislehurst, Kent, and DIXON, R. G., 162, Westmount Road, Eltham Park, London. Dec. 6, 1932, Nos. 34555/32 and 6886/33. [Class 40 (iv).] In a code - translating register - controller system, the A-digit switch subsequently acts as a marking switch for the first code selector. The invention is described with reference to two systems; one of which is identicalwith that described in Specification 411,455 in which for calls to exchanges provided with alternative direct and tandem routes both direct and tandem junctions are normally marked by a single translated digit and the first code selector proceeds automatically to search the tandem junctions if all the direct junctions are busy. In the other system, Figs. 4-6, a 25-point single-motion switch associated with a common control circuit multipled to a plurality of first code selectors is first set to one of its first five positions in response to the A- digit to control the selection of one of an appropriate group of register-controllers, is then set by the first translated digit from the sub-normal position 6 to one of the positions 8 to 20 to mark a group of outlets, and in the case of calls to exchanges provided with alternative routing facilities may be further set from position 21 to one of positions 22-24 to select a group of tandem junctions. For calls which must always be made via a tandem route, the first translated digit of one impulse sets the marking switchto position 7 from which it proceeds automatically to position 21 and then responds to a further digit to select a tandem junction. Seizure of control circuit and registercontroller ; reception of digits. The first code selector. Figs. 4, 5, is seized overleadc, contacts on2, fon2, and wiper DS8, and relays A, B, JB, K, N, CA(i) operate. Impulses of the first digit are repeated by relay A to relays P and Q which operate through a cycle for each pair of impulses. At the end of each even impulse magnet DSM advances switch DS1-DS8 one step and if the digit is odd relays P, Q remain energized. In position 1 of wiper DS4 relay OM is operated and locks and at the end of the digit when CA releases, latch magnet CLM drives switch CF1-CF18 in search of an idle register-controller in the group marked by wiper DS3, one of the two sets of wipers CF1-CF8, CF11-CF18, being connected up in accordance with the condition of relays WA, WB, of which WA is energized for particular pre-arranged groups over jumperings from the bank of wiper DS7. When a register-controller is found relays T, HA, HB operate over lead p, and relay AA operating over a loop in the register-controller advances switch DS1-DS8 to position 6 in which CB(i) operates. Relays TZ, B, in the register-controller energize and the units register U1-U8, which also acts as a digit distributer is stepped to its first position over wiper U2. If the first digit was odd, relay Q, Fig. 6, operates over wiper U4 and lead b. The second digit is repeated by relay A over lead pu and relay C(ii) to magnet SM of the sending switch, the third digit to magnet CSM of the output-controller switch, and the numerical digits to registers TH-U, relay C which effects the stepping on of wiper U6 after each digit being provided with a parallel highresistance winding (i) to ensure that the relay energizes fully. If the second digit is greater than five, switch CS1 before receiving the third digit is moved to a second normal position (No. 12) so that the third digit will select a position in the second part of its bank. In position 3 of U2, latch magnet BLM is energized to advance the translating switch BC1-BC16 to a position corresponding to the code dialled, when T operates and energizes TT which completes restoring circuits for magnets SM, CSM. When both switches have reached normal relay SS operates over wipers S4 and CS1. Local or direct-junction call. Relay SS extends earth over contacts b3, co3, ss1, sn4, sz5, and wiper CS2 for relay IG which connects interrupter 11 to magnet SM of the sending switch. After the second step, the outgoing loop across relay D is replaced by a direct loop over interrupter 12, and impulses up to a possible maximum of 14 are repeated by relay AA to magnet DSM over CB(ii) until relay SZ operates over wipers S7, BC1, CS4 (or BC12, CS3 if Q is operated) and releases IG. The sending switch returns to normal, a sufficient pause between digits being assured by arranging that four of the restoring steps are controlled by interrupter 11. When relay CB falls back, latch magnet LM operates over wiper DS4 and the first code selector hunts over the group of outlets marked over wipers DS5 and DS6 in series, relay WS being operated over bank DS3 if the lower or even banks are selected. When an idle outlet is found, relays TA, TB operate, and the outgoing loop is switched through to the succeeding switch. Further translated digits are sent out in similar manner and relay SN(i) then operates over terminal dc to connect up wiper CS3 and advance the control switch to position 13 for the transmission of the numerical digits. The transmission of the thousands digit is dependent on the hundreds register having moved off normal and on the release of polarized relay D which energizes over a junction when seized and releases in response to a signal sent back when a coder or incoming selector is ready to receive impulses. After the units digit has been sent relay CO operates to release the register-controller and to complete a circuit over wire h for operating relay H(i) which switches through and releases the control circuit. Alternative routing. Direct junctions to exchanges with alternative-routing facilities are connected in the even (lower) banks of the first code selector or are accessible over these banks if connected at a succeeding code selector. Tandem junctions are connected in the odd (upper) banks. For all even-bank outlets which are not direct junctions to exchanges with alternative-routing facilities relay OF is operated over wiper DS7. If the first codeselector encounters a busy condition in a group of direct-junctions to an alternatively-reached exchange, relay CT operates over last contacts in the even (dotted-line) bank and opens the circuit of relay OM during the release period of which 50-volt booster positive potential BP is connected over the positive lead to operate relay R in the register-controller over rectifier Rl. Relay R locks itself over lead ar, holds up further sending, and operates relay AR, Fig. 6, which completes a circuit over terminal pdc for advancing switch CSM a further step. In the first code selector, when OM falls back, relay AR(i), Fig. 5, operates, and relay WS is released to switch over to the odd banks and to release relay TA. Switch DS1-DS8 now moves to position 21 in which wiper DS4 connects direct earth to lead ar releasing relay R in the register-controller. Digits for the tandem route are sent out under the control of further wipers of switch BC1-BC16 in later positions of the control switch CS1-CS8. The first of these (2 to 6 impulses) is repeated by relay AA over wiper DS3 to relays P, Q, advancing switch DSM to one of the positions 22-24 in which the appropriate tandem group is marked over wiper DS5 or DS6 according as the digit is odd or even. When relay CO in the register-controller operates, ground is extended over wiper U4 and lead b to operate relay NA which releases N and transmits a booster impulse over the outgoing c-wire to switch in a feed at a repeater. The release of N completes the circuit for switching relay H. If the direct junctions are taken from a subsequent code selector, relay WS remains operated when OM falls back owing to the operation of OF and the booster battery signal to the register-controller to prepare for tandem routing is sent back from the selector encountering the busy condition. On the operation of AR, Fig. 5, the marking circuit is opened at contact ar3, relay TA releases, and the selector rotates to its last position and operates CT so that search for the selection of an idle tandem junction occurs as before. Normal tandem call. Relay AR(ii), Fig. 6, operates over a jumper to direct-ground ts when SN operates if a single fee is required or over terminal te and wiper U3 if multi-metering is required. The first translated digit consists of one impulse, advancing switch DS1-DS8 to position 7 in which DT(i) operates in series with CT. When OM releases, the switch moves to position 21 and then responds to a digit for the selection of a tandem junction, further junctions in each group being available owing to the operation of DT. The next digit sets a metering switch at the outgoing repeater. Busy conditions. If the first code selector encounters a busy condition, relay LC(i) operates over the penultimate contact of the bank of wiper P or the last contact of the bank of wiper P2 to connect up busy tone BT and release the register-controller. If the switch CF1-CF18 fails to find an idle registercontroller, relay LC(ii) operates over last contacts of the switch to give the busy tone. Irregular operation. If no impulses are received within a given time, relay Z operates, energizing LC(ii) and causing the code selector to move to penultimate contacts at which TA operates over lamp PL and wiper P2, WS being operated over wiper DS3, and S(ii) locked over wiper DS2. Relay PG operates when H switches through to ground the incoming test wire and connect up an alarm. If delay occurs after the first digit, relays Z, LC(ii) operate, and NU tone is connected up. Relay S being released, a series of special tone circuits is marked and the selector hunts for an idle one of these to supply a special tone and release the control circuit. Call to zero operator. In response to digit 0, relay T operates immediately over normal contacts of wipers CF4, CF8, and wip