Patent GB-573885-A (GB)
Title: Improvements relating to telephone systems
IPC: H04Q3/42
Filed: 1943-12-24
Abstract: 573,885. Automatic exchange systems. SIEMENS BROS. & CO., Ltd., and LONG, D. P. Dec. 24,1943, No. 21588. [Class 40 (iv)] In a code-translating register-controller, a two-motion switch is used to receive the B and C digits, all the other functions normally performed by switches being taken by relay chains which, in the case of the digit registers, the last of which acts also as a digit distributer and sending and pause-timing switch, are 4-relay chains of the kind described in Specification 567,633, in which a previously energized high-speed relay is connected by each impulse to the chain and is shunted out when the corresponding chain relay operates. The sender control switch is a somewhat similar chain which builds up once for the digits of the office code and a second time for the numerical digits. Impulses are generated by a self-interrupting relay system of the kind described in Specification 462,773 with means for varying the impulse rate in accordance with the route selected. The register - controller has the usual facilities such as means for routing calls to manual boards in response to a particular office code or to the dialling of O as the A-digit. Means for delaying the transmission of impulses until CCI equipment is ready and for releasing the A-digit switch and consequently itself if a spare code is dialled or if dialling is unduly prolonged. The apparatus can be put out of service by a key KD. Registering wanted number. When the register-translator is seized by the A-digit switch, A pulls up over the test wire, followed by B, BA, after which A is dependent on the pulse wire PU. The relays of the numerical registers MR ... UR co-operate with a common high-speed relay AX, which is normally operated and, on operation of the impulsecontact a1, is connected to the appropriate register to operate the next relay therein, being shunted out by the operation of the latter. During the operation of the units register as digit-distributer, it co-operates with a highspeed relay CX energized by the operation and connected to the chain by the relapse of the C relay. The transfer of the impulse circuit from the BC-switch to the relay registers is effected by a relay MT and, at the end of the tens digit, a relay UT releases UZ in the units register in readiness for the reception of the units digit at the end of which a circuit is made for the releasing winding of MT. Transmitting number. Relay S pulls up when the C-digit has been received and connects up the impulse-generating relay P, impulses from which build up a sending chain CA ... CD which is of the same kind as digitregisters and involves a high-speed relay PX which is operated when S pulls up. Simultaneously, impulses are sent over the outgoing circuit by a relay PA controlled by P. The first digit is terminated by the operation of SZ over contacts of the sending chain, the translating frame and the wiper 1 of the BC switch to release P, PA, PX and the relays of the sending chain. SZ locks and energizes J which connects the previously operated highspeed relay SX to the first relay SA of an outsequence chain SA ... SF to operate SA which then shunts out SX. The circuit provides for two methods of timing the intertrain pause. J, on operation, inserts a highspeed relay VA in the outgoing loop and releases S. If a clean metallic circuit exists, VA pulls up and charges QJ and, when the selector ahead switches through, falls momentarily to cause the discharge of QJ to operate another high-speed relay VB which locks and unlocks SZ. Alternatively, since the release of S reconnects P, PA, PX, the sending chain builds up again and, after 5 impulses, SZ is released, if it has not already been released by VB, and the chain relays fall back. On the relapse of SZ, J falls, allowing S, SX to pull up again and the next digit is sent in accordance with the jumpering to wiper 2 of the BC- switch. After this digit, SB pulls up and so on, each relay of the out-sequence chain releasing the previous one except SE, SF which remain operated. When the last digit of an office code less than the maximum has been sent, the wiper next connected up by the sequence relay will be connected to DCO and this causes the chain to build up rapidly to SF to switch the marking ground from the BC-switch wipers to contacts of the digit registers, the marking arrangements of which are as described in Specification 471,987. SE arranges for the release of the digit registers as soon as the corresponding digit has been sent. After the transmission of the units digit, CO pulls up and releases the A-digit switch which releases the register-controller. The re-operation of S at any stage is prevented if the digit next to be sent has not been received. High-speed impulsing. Certain terminals of the BC-switch are jumpered to terminal lc. When the wiper resting on such a terminal is connected up, PF operates locks and causes the operation of the next of the sender control relays, and disconnects a resistance associated with relay P to cause impulses for the subsequent digits to be generated at a greater speed. On the operation of relay J, the speed is reduced to normal for measurement of the inter-train pause.