Patent GB-462180-A (GB)
Title: Improvements in or relating to automatic or semi-automatic telephone or like exchange systems
IPC: H04Q3/42
Filed: 1935-09-03
Abstract: 462,180. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd., WRIGHT, E. P. G., HARTLEY, G. C., and WYNDHAM, P. I. Sept. 3, 1935, No. 24554. [Class 40 (iv)] Translating devices for transmitting an alternative - routing code when a busy condition is encountered are associated in common with the last numerical selectors in the exchange-selecting route, the appropriate tandem code being selected by a determination of the position to which the associated selector has been set. Two embodiments are described, both employing selectors of the two-co-ordinate type. In the first, the selector responds to the second and third code digits transmitted by a register-translator and then hunts in the selected group, whilst in the second, the selector responds directly to the second of two dialled digits denoting the wanted exchange. First system, Figs. 1-3. On seizure of the selector, relays A, B, C respond and the second code digit is repeated to vertical magnet VM after which relay E operates so that the third digit passes to rotary magnet RM. Between the relapse of relays C, E, relay HA tests the outlet associated with the upper set of wipers and if this is busy relay G operates over wiper P1 so that HB tests the other outlet. If this also is busy, HB and G are short-circuited over P2 and the latter releases. The rotary magnet RM operates over contacts NR2 upon the release of E and testing of succeeding outlets proceeds in similar manner. If all outlets are busy, relay HS operates over bank D when the end of the group is reached, reverses the connections to the incoming loop to prevent further operation of the register-translator, marks the selector in the bank T of the finder FM, Fig. 2, and completes the starting circuits S of idle finders. When the selector is reached relay P is operated, connecting relay T to a resistance BSP common to all the translating circuits to ensure that only one uses the marking multiple vr-VW at the same time. When the multiple is free, relay T operates and at the next break of springs MS relay B operates and connects the springs to vertical magnet VM, Fig. 2. When the marked level is reached, relay C operates over wipers vr, VW, fm2 and releases ST so that the springs MS are connected to relay A which repeats impulses simultaneously to rotary magnets RM of the switch VR, Fig. 2, and the selector, Fig. 1. When the selector reaches its eleventh terminals and the translator has therefore been set to a position characteristic of the wanted exchange, springs S2 remove a short-circuit from relay EL which operates to release the selector and to connect relay A to a loop over wipers fm5, fm6. Relay D operates to break the impulse circuit and connects relay F to start lead S of the translator switch, Fig. 3, which is of the type described -in Specification 354,405 having a separate bank for each routing-number. Relays TA, F, G operate followed by TC when springs MS, Fig. 3, open. Magnet TM is impulsed by springs MS and the translated digits for routing the call via a tandem exchange are transmitted from springs IS over one of the leads P and wiper vrm2 to relay A, Fig. 2, which repeats them over wipers fm5, fm6 to relay A, Fig. 1, to control the selector as before. When all the digits have been transmitted, relay TB operates, restoring the translator switch to normal and re-operating relay F which releases G and D so that the release magnet ZM of switch VR, Fig. 2, is operated. At the selector, relay EL releases due to the opening of its locking circuit over wiper fm2. The same translating circuits may be associated with selectors of more than one numerical group in which case to provide a distinction when corresponding contacts in selectors of two groups are each used for the last line of a junction-group, an additional step may be given to magnet RM, Fig. 2, in one ease by employing the dotted connections including relay E. Statistical metering. A metering relay D may he included in the start lead S to the translator switch to operate a meter OM which records the number of times the preferred route is busy, whilst a meter connected over lead CML, Fig. 1, and operated over eleventh stepsprings S2 of the selector records the number of times the tandem route is not available. Second system, Fig. 4. When the selector is moved off-normal, relay X operates closing start circuits for link circuits SF. RF. Relays P, PP operate when the selector is reached by finder SF, and switch RF then hunts for an idle translating circuit characterized by absence of ground on wiper rfm1. If the selector finds a free direct junction relay X is de-energized by the switching relay and the translating circuit is released unused. If the selector fails to find a free direct junction on a level on which alternative-routing facilities are provided, relay K operates over eleventh-step-springs S1 and relay T also operates connecting the incoming leads to relay RA and the relay A to an impulsing loop. Relays RA, RB, BB operate, and normally-operated relay ON releases to mark the circuit busy. Relay MG energizes over resistance BSP when the common marking multiple is free, and magnet BSM is operated. The level-marking banks vm of the selectors of different numerical groups are wired to different groups of contacts in bank bsm1 so that the position to which switch BSM is set is individual to the wanted exchange. When this position is reached, relays M, MF operate, releasing the selector, magnet SSM is connected to springs MS, and routing digits determined by jumperings from banks bsm2, bsm3 to bank ssm2, followed by numerical digits (which have in the meantime been received by relay RA and recorded), are then sent out in known manner by springs IS. In the seventh position of wiper scm3, relay R operates unlocking PP which in turn releases T, K, and the translating circuit. If the selector fails to find a free junction on a level on which alternative-routing facilities are not available, relay M operates over a multiple lead connected to a particular contact in bank bsm1 and relay R operates immediately over bank bsm4 to release the translating circuit, a busy signal being given. Timed-release. Relays ZA, ZB operated in succession by a 9-seconds pulse operate relay R to release the translating circuit.