Patent GB-280576-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/42
Filed: 1927-11-10
Abstract: 280,576. Associated Telephone & Telegraph Co., (Assignees of Richardson, R. G.). Nov. 10, 1926, [Convention date]. Automatic exchange systems.- Separate register-controllers are proare provided for registering and translating the office designation and for registering and retransmitting the numerical designation and are associated with a calling relay-group TRG, Fig. 1, over separate non-numerical switches ODS, LDS, respectively. A numerical register-controller is not taken into use until the first of the two office digits has been registered and if these two digits when registered denote a special operator the numerical register-controller is immediately released. The invention may also be applied to systems in which office register-controllers are reached over A-digit switches. Office register-controllers, Fig. 2. The trunk release relay 111, Fig. 1, connects stepping magnet 142 in series with switch relav 141 and connects the mid-point of this circuit to the test wiper 154 so that switch ODS hunts in the usual manner. When an idle office register-controller, Fig. 2, is found, relay 141 operates and connects earth to wiper 154 energizing relay 222. The first office digit is repeated by relay 110 over conductor 163 and wiper 214 to the vertical magnet 216 of the office register OR. When the switch S moves on at the end of the digit, wiper 213 connects earth over resistance 220 to conductor 165 to initiate the seizure of a numerical register-controller as referred to in the next paragraph. The second office digit is similarly repeated to the rotary magnet 217, and wipers 214 - - 245 are stepped on to, say, terminals 251 - - 255. When switch S moves to its 3rd position, wiper 213 connects direct earth to conductor 165 to effect the operation of relay 113 which switches the incoming impulse circuit over to the numerical register-controller. Wiper 215 of switch S connects up interrupter I to magnet 235 which steps round the sending switch SS and sends out impulses at contacts 239 in the well-known manner. In the present example, a routing number 79 is sent out and on the movement of the output sequence switch S<1> to the 3rd position, a circuit is completed over wipers 212, 243, terminals 253, 12, and lead 163 to operate relay 114 which switches over the outgoing impulse leads to the numerical registercontroller. Relay 114 also releases relays 141. 222, and the office register-controller is released in known manner. Numerical register-controller, Fig. 3. The connection of earth over resistance 220 to conductor 165 when the first code digit has been dialled completes a circuit over the lower winding of relay 113 for relay 170 wich causes the switch LDS to hunt in the usual manner. When an idle numerical register-controller is reached, relays 322, 324 operate. The connection of direct earth to conductor 165 when the last code digit has been registered causes relay 113 to operate so that succeeding trains of impulses are repeated over front contact 126 to the magnets 351 - - 354 of the numerical registers. When the last routing digit has been sent out, relay 114 operates as referred to above to connect impulsing conductors 195, 196 to the outgoing trunk conductors 101<1>, 103<1>, and relay 321 energizes over the loop, locks up, and removes its upper winding from the loop. If by this time the first digit register has moved off normal, relay 324 falls back, the interrupter I<1> is connected to magnet 335 of sending switch SS<2> and the latter operates to retransmit the numerical digits in known manner. The provision of parallel circuits over the wiper 312 of sequence switch S' and normal contacts of the digit registers delays the release of relay 324 to initiate the retransmission of any digit until that digit has been received. When the last digit has been sent out, wiper 312 connects earth to conductor 193 to energize relay 112 which switches through and releases relays 113, 114, 170 and the numerical register-controller. Call to special operator. An idle numerical register-controller is seized at the end of the first code digit as before but if after the second digit the office register OR is set to terminals 251<1> - - 255<1> corresponding to the designation of a special operator, relay 221 energizes over terminals 11, 255<1>, and wiper 245. When, there. fore, series relay 202 pulls back, earth is no longer connected to the conductor 165 and the numerical register controller is released. Switching relay 112 is energized after the transmission of the routing digits over a circuit including contact 126<1>, conductor 163, terminals 12, 254<1>, and wipers 244, 212.