Patent GB-250342-A (GB)
Title: Improvements in or relating to automatic or semi-automatic telephone systems
IPC: H04Q3/42
Filed: 1925-01-14
Abstract: 250,342. Automatic Telephone Manufacturing Co., Ltd., (Automatic Electric Co.). Jan. 14, 1925. Automatic exchange systems.-In a system in which a translating frame is common to a number of register controllers, the route codes are sent out under control of a common counting device connected to one side of the frame the other side being connected to the office registers. Terminals for which no digit is to be sent are jumpered at the frame to a booster battery, and a marginal relay causes the sender control switch to skip the blank positions. The subscriber digits are sent out under control of an individual relay counting chain using a single relay per impulse. The Specification describes a substation circuit with only one hook-switch contact and a trunk circuit with means for enabling the calling party to hear impulses being sent by the register controller. The vertical magnet of the first code selector is arranged to disconnect the change-over relay at the end of its stroke. Substation A. The hook switch comprises only one contact and the impulse transmitter has three off-normal springs for shunting the talking instruments. A three-terminal condenser 3 is arranged as shown to prevent the operation of the number dial from having any effect until the receiver is removed. Line switch LS. This forms the subjectmatter of the divided Specification 250,879. Trunk circuit TC and switch DS. Line relay 41 energizes release relay 42 which completes a hunting circuit for the switch DS and returns ground to hold up the line relay 16. When an idle register controller is found, switching relay 52 connects the transmitting loop 62, 63 to the outgoing line, completes the circuit 65 for impulsing the register controller and grounds wire 64. The condenser 39 is just large enough to enable the subscriber to hear the impulses sent by the register controller to relieve the tedium of the interval between the termination of dialling and the ringing of the wanted party, and to indicate that the exchange apparatus is working. first code selector S. Line relay 72 pulls up over the loop in the register controller and energizes release relay 73. The first digit is repeated to vertical magnet 40 and change-over relay 74 in parallel. At the end of its stroke the vertical magnet disconnects the relay 74 to ensure that it shall always take the same time to fall back at the end of a digit independently of the condition of the line relay. The relapse of relay 74 at the end of the digit energizes the rotary magnet 79 which interacts with the stepping relay 75 in the usual way until the connection is extended by relay 76. Metering. When the called party replies, the usual current reversal energizes the electropolarized relay 71 which short-circuits its upper winding and the resistance 83 in the talking circuit and is subsequently held by the polarizing winding. At the same time. it short circuits the resistance 84 in the holding wire, thus operating the marginally adjusted meter M. Registration of wanted number. Dialled digits are repeated to the operating magnets of the Strowger office register OR and the digit registers DR1 - - DR4, the sequence being controlled by a switch S which takes a step after each digit under control of relays 101, 102. Transmission of office code. The terminals of the office registers are multipled to one side of a common frame IDF, the other side of which is connected to the terminals of a common counting switch CS of back-stroke drive type and continuously driven by an interrupter 304. The interrupters 305 - - 308 break contact at the same time as the interrupter 304 but make it slightly later. When the office letters have been registered, wiper 108 connects the pick-up relay 205 to the first terminal of the switch CS, and when wiper 310 reaches this terminal, relay 205 pulls up and locks itself. The energizing circuit is broken at 329 at the next energization of the stepping magnet 309 to prevent any other register controller from starting until the switch CS is again in its first position, and an instant later the make period of the other interrupters begins and an impulse is sent to relay 204 with repeats it over the trunk. At each subsequent step the switch CS grounds one of the stop wires 311 - - 320. The relay 204 continues to receive impulses until wiper 310 reaches the terminal to which the relay 207 is connected via the wiper 115 of the sender control switch S<1> and the office register. Relay 207 pulls up in this circuit, disconnects the impulse relay and energizes the stop relay 206 which disconnects the wire 116 to advance the switch S<1> and locks itself over a contact of relay 205 which it unlocks. Relays 205, 206 fall back in succession sluggishly to provide hunting time. In the case of long digits this period is taken up by the advance of the switch CS through its last few terminals which are dead. When the switch CS again reaches the pick-up position the sending of another digit begins. I.D.F. terminals for which no digit is to be sent are jumpered to booster battery 301, and when wiper 115 reaches such a position, relay 202 which is marginally adjusted and does not pull up in the normal stopping circuit, is energized in series with relay 207, and completes a self interrupting circuit for the driving maget 113 and the switch S<1> is stepped automatically through the blank positions. Transmission of numerical code. In its fifth position, the switch S<1> energizes relay 201 which locks up, connects ground to wiper 115 in place of the relays 202, 207, disconnects the pick-up wire 119 and connects the filth terminal of wiper 115 of the switch S<1> to the register DR1. When relay 206 falls back, the impulse relay 204 is connected to the interrupter 305. The first impulse energizes relay 208 which completes a locking circuit for itself in series with relay 403. This circuit does not become effective until the end of the impose whereupon relay 403 pulls up, locks itself unlocks relay 208 and prepares relay 209. The next impulse therefore energizes relay 209 which locks up in series with relay 411 this circuit becoming effective only at the end of the impulse whereupon relay 411 pulls up, locks itself disconnects relay 209 and prepares relay 208. The chain continues to be built up in this way, and since relay 403 energizes the pick-up relay 205, each impulse after the first is repeated over the trunk. The digit is stopped by the energization of the relay corresponding to the setting of the digit register. Stop relay 206 is then energized over 256 and unlocks the counting relays. Release of register controller. In its final position, the switch S' grounds wire 65 to energize the switching relay 43, Fig. 1. Relays 41, 42, 52 fall back in succession. In the register controller, relay 203 falls back, completes a homing circuit for the switch S', short circuits relay 201 and enegrizes the release magnets of the switch S and the registers.