Patent GB-235142-A (GB)
Title: Improvements in or relating to automatic or semi-automatic telephone systems
IPC: H04Q3/42
Filed: 1925-03-16
Abstract: 235,142. Automatic Telephone Manufacturing Co., Ltd., (Assignees of Stehlik, R. F.). June 9, 1924, [Convention date]. Automatic exchange systems.-The sending switch of an impulse sender after sending a digit advances to the next of a number of starting positions less than ten steps apart, or remains stationary if already in a starting position. The invention is described in connection with a code-translating register controller of known type. The sending switch SS, Fig. 3, has two starting positions, 240, 239, and a corresponding number of stopping wipers 236, 237, for controlling the number of impulses in a digit. The proper wiper is made operative by the energization of one of a pair of relays 204, 205 according to the position from which the next digit is to start. There may be as many as ten starting positions, in which case the switch remains stationary after sending a digit. According to the Specification as open to inspection under Sect. 91 (3) (a) a standard 25-point line switch may be used with the connections as shown duplicated in the two halves of the bank. Selection of an idle register controller. A subscriber A, Fig. 1, is connected in known manner bv his line switch C to an idle trunk circuit TC the line and release relays 31, 32, of which complete a circuit for a switch DS which operates like a line switch to select a register-controller. The operation of switching relay 81 connects the outgoing impulse wires 91, 92 to line relay 51 of group selector D and the impulse contact of line relav 31 to the wire 94. Relays 51, 52 pull up and prepare for the operation in known manner of selector D. Registration of wanted number. The two office digits are recorded on a Strowger register OR, Fig. 4. and the remaining digits on simple switches DR1 - - DR4, Fig 5. The successive connection of the register stepping magnets to the impulse wire 94 is effected by a switch S the stepping magnet 105 of which receives an impulse at the end of each digit from a sluggish relav 101 included in the impulse wire, the duration of the impulse being governed by a sluggish relay 102. Transmission of impulses. When the office code has been registered, the switch S connects interrupter 114<1> over wiper 108 to the stepping magnet 231 of the back stroke drive sending switch SS. The first step energizes pick-up relay 202 so that subsequent energization of magnet 231 separate the impulsing leads 91, 92. If the switch starts from the position shown, relay 205 which becomes energized over contact 240 and is subsequently locked to contact 212 of the stopping relay 203 gives the control of the stopping relay to wiper 236. At the end of the digit, relay 203 bridges the wires 91, 92, unlocks relay 205 and completes a self-interrupting circuit over 231, 213, 232, 234 to step the switch SS to its next starting position. If the first digit was five, wiper 234 is on terminal 238 and the switch does not.move, if less than five wiper 234 stops on terminal 238 and if more than five in the position shown. If the second starting position is to be used, relay 204 pulls up over terminal 239 when the pick-up relay falls back and on the subsequent relapse of relay 203 the switch starts up, re-energizes the pick-up relav and transmits a digit under control of wiper 237. The sending switch is associated in succession with the wipers of the registers OR, DR1 - - DR4 by a back stroke drive switch S1 the magnet 111 of which is energized by the pick-up relay 202 and released by the stopping relay 203. If fewer than four digits are to be sent for the office code, the switch S<1> is stepped through the blank positions on a self-interrupting circuit over the skip terminal on the IDF. A wire 222 connecting the stop relay 203 to the normal terminals of the registers DR1 - - DR4 ensures correct functioning if the calling party is slow in dialling the numerical part of the number. Release of register-controller and completion of connection. In its final position the switch S<1> grounds the wire 94 to energize switching relay 33 of trunk circuit TC and relays 31, 32, 81 fall back. Relay 201 which has hitherto been held over wire 93 since the register-controller was seized, falls back and completes at 206 a homing circuit for switch S1 and at 207 a circuit for the release magnets of the switch S and the registers.