Patent GB-447068-A (GB)
Title: Improvements in or relating to electric signalling systems
IPC: H04Q1/32
Filed: 1934-11-09
Abstract: 447,068. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd., 63, Aldwych, London.-(Assignees of Williford, O. H.; 100, Morningside Drive, New York, U.S.A.) Nov. 9, 1934, No. 32375. Convention date, Nov. 11, 1933. [Class 40 (iv)] [See also Group XL] Impulse responding contact-making relays, in automatic telephone systems for example, are replaced by gas discharge tubes. In one arrangement for controlling the setting of a relay chain in a register-controller, the discharge tube having its grid connected to the impulse circuit so as to be rendered conducting by impulses, has its anode connected to the first relay of the chain over contacts of the relay so that on receipt of the first impulse, the relay is operated, opens the anode circuit to stop the discharge and then connects the second relay of the chain to the anode circuit, whereupon similar operations ensue on the next impulse. The impulses may be very rapid and less than the operating times of the chain relays since their only function is to initiate discharges of the tube. The dialling relay may thus be quicker to release than the usual slow relay, and its release at the end of the train is effected by making the last impulse of the train longer. A similar arrangement is used to count off reverting impulses in the register-controller. Registering impulses, Fig. 1. Substation 100 is connected in known manner to the registercontroller of which the counting chain 104 ... 109 and one of the registers 111 ... 115 is shown. The loop circuit extends from resistance 101 to a dialling relay 102 over a second winding of which dial tone is fed. The gas discharge tube 103 has its anode connected over back contacts of all the counting relays to relay 104, its grid connected to the leg containing resistance 101 and its filament connected in series with a resistance across the battery which provides anode potential. Relay 102 pulls up, and the first break disconnects the grid from negative battery over 102 so that it is positively biassed over resistance 101 to break down the tube. Relay 102 holds during the train. Counting relay 104 pulls up, the discharge continuing after the loop has been re-made until 104 breaks the anode circuit and connects it to the next counting relay 105, relay 104 holding to the front contact of 102. The first five impulses are repeated in turn to relays 104 .. 108, the last mentioned of which connects up 104 again, the fifth impulse also operating 110 which completes for relay 109 a short circuit removedon the seventh impulse to operate the relay for the purpose of making additional circuits for register relays 114, 115. Each counting relay excepting 106 releases the preceding one, 105 and 106 being released by 107, and the register relays 111 ... 114 being left operated in different combinations according to the digit dialled. The dial is constructed so that the last break is longer than the remainder and releases 102 which releases the counting relays and may transfer the circuits of the chain to the next register relay group. Control by reverting impulses, Fig. 2. The fundamental circuit extends over relay 200 and cam 201 at the group selector, resistance 204 and contacts of relay 219 in the registercontroller to ground over resistance 202 at the selector, the grid-cathode circuit of the discharge tube 205 being connected across resistance 204, and its anode being connected over contacts of the register relays 206-209 to a relay in chain 210 ... 219 dependent on the digit registered, and thence to positive battery. The cathode is connected to negative battery. Relay 200 locks independent of cam 201 and operates the up-drive magnet 203 so that ground (positive battery) impulses are reverted from commutator 222 and applied to the grid of the tube to break it down. As before, the discharge continues until the anode circuit is broken by a counting relay, the circuit being then connected to another counting relay. When the counting chain is saturated, 219 opens the fundamental to release 200 which stops the selector. Relay 219 also grounds lead 220 to prepare the register-controller for controlling the next selector stage, such preparation involving opening the chain circuit at X to release it. The markings by the register on the relay chain are such that starting from relays 219 to 215, respectively, the chain is saturated by 1 to 5 reverting impulses, the chain being counted out in ordinary sequences. When the chain is to be satisfied by more than 5 impulses, however, the markings are irregular and the chain relays are not operated in sequence. The Specification as open to inspection under Sect. 91 comprises also the arrangements shown in Figs. 3 (Cancelled) and 4 (Cancelled), in which the anode and grid circuits of the tube are connected to separate secondary windings of a transformer, the tube being rendered conducting and non-conducting by successive surges of opposite polarity occurring at the beginning and end of an impulse. In Fig. 3 (Cancelled), battery is connected between two secondaries so that the grid of tube 202 is biassed negatively over S1 and the anode is connected to positive potential over S2. The filament is heated from the battery over a resistance network 204-206. When the loop is first completed over primary P, potential surges arise in the secondaries S1, S2 which are so poled that the grid is made less negative and the anode more positive, and the tube breaks down to operate 203 which is followed by an ordinary slow releasing relay 208. On the first break, surges occur in the reverse direction, the tube becomes non-conducting and 203 falls back to repeat an impulse over wire 209 to a selector, repeater or recorder. Succeeding impulses are repeated in like manner. The arrangement shown in Fig. 4 (Cancelled) is similar but utilizes a cold cathode tube having two cathodes, one connected to negative battery and the other, a control cathode, to secondary S1 over a resistance. This subject-matter does not appear in the Specification as accepted.