Patent GB-252041-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/42
Filed: 1925-01-08
Abstract: 252,041. Western Electric Co., Ltd., (Deakin, G., and Polinkowsky, L.). Jan. 8, 1925. Automatic exchange systems; metering.-In a register-controller system of the reverting impulse type, if no impulses are sent to the register-conroller within a predetermined period after the register-controller is taken into use, or if undue delay occurs between the dialled digits the register-controller is released and an attendant's lamp is lighted. The invention is described as applied to a system in which the register-controller is taken into use from a link circuit terminating at one end in a line finder and at the other end in a group selector, and having associated therewith a controlling sequence switch 15. In case of dialling delay, or if no impulses are received (this may be due to a fault in the calling loop), a relay 6 is energized by a timing device in the registercontroller, and causes the sequence switch 15 to move to a position in which the register-controller is released and a signal lamp 21 lighted. The relay 6 may also open the metering cricuit to prevent metering. Normal operation of link circuit. The starting circuit for the finder at the incoming end of the link extends over the starting relay 3 which closes a circuit 23, 12, 47, 39 for the finder power magnet 28. When the calling line is engaged, a test relay 1 energizes over the test wiper h, opens the circuit of the power magnet 28, connects its secondary low-resistance winding in shunt to mark the calling line busy, and energizes a relay 5 which completes a circuit for relay 6. Relay 6 closes a circuit to drive the sequence switch to its third position, de-energizes relay 3, and energizes switching relay 9 in series with the calling line cut-off relay. Relays 1, 5, and 6 now relapse, but relay 9 remains held over sequence switch contact 39. In the third position of the switch, the register-controller finder (the wipers of which are shown at the bottom of the drawing) hunts for an idle register-controller, the circuit for the power magnet 30 extending over contacts 39, 47, 12, 13. When an idle register-controller is engaged the test relay 1 energizes over test wiper g, disconnects the magnet 30, and connects up its secondary winding to mark the register busy. The test relay 1 causes the response of relays 5, 6 and the sequence switch 15 is then driven to its fifth position, whereupon relays 1, 5, 6 relapse. Between the fourth and ninth positions the calling loop is extended to the in-impulsing leads of the register-controller over wipers a, b, and a relay 8 is energized by ground returned from the register-controller over wiper e. In the fifth position the fundamental circuit is completed from ground over brush d and energizes relay 2, which drives the sequence switch 15 into its sixth position, wherein the trip spindle of the first group selector is rotated by magnet 32, producing intermittent short-circuits around the stepping relay in the register-controller in the usual way. When the register reaches normal, the opening of the fundamental circuit de-energizes relay 2, which moves the sequence switch 15 to its seventh position, in which the relay 2 re-energizes and the brush carriage magnet 40 rotates the brushes i, j, k to select an idle trunk. Upon an idle trunk being engaged, the test relay 1 pulls up, connects its middle winding in series with its right-hand winding in shunt across its left-hand winding to mark the trunk busy, and deenergizes relay 2, which drives the sequence switch to its ninth position in which the fundamental circuit is extended to the next switch and the register-controller completes its operations. When the last register has been restored to normal, the circuit of relay 8 is opened at the register-controller, the relay 2 is de-energized, and the sequence switch 15 is driven into its tenth or conversation position in which the register-controller is disconnected. Fault signal and release. The register-controller is provided with a time device which, if no impulses are received before the expiration of a predetermined period after the register-controller is taken into use, returns earth over brush f to energize relay 6; this condition may arise if the calling party omits to dial or if the register-controller is seized due to a permanent fault on a calling line. The relay 6 blocks up over its inner left-hand armature and drives the sequence switch 15 to its eighth position in which a check is made to ascertain whether the group selector of the link is in its normal position. If it is, relay 1 is energized over a home contact 41 and opens the circuit of relay 2 which would otherwise energize in the eighth position and arrest the sequence switch. The sequence switch moves to its ninth position over the lower right contact of cam 16 and then to its thirteenth poistion over the outer right-hand armature of relay 6 and the upper left contact of cam 38, thereby disconnecting the register-controller. In the thirteenth position a signal lamp 21 is lighted over cam 43 and the arm of a timing switch 45 rotated by magnet 48. After the expiration of ten minutes, the circuit is transferred to an interrupter 46 to flash the lamp. If an attendant plugs into the jack 22 to attend to the fault, ground on the sleeve of the plug short-circuits relay 9, relay 4 relapses, and a circuit 39, 38, 13, 12 is closed for relay 2, which drives the sequence switch to its fourteenth position in which another interrupter 44 of different periodicity is connected to the lamp 21 to indicate to other attendants that the fault is being attended to. When the attendant takes down the plug, if the fault still exists, relay 4 is held over the loop, but if the fault has been removed, relay 4 is not energized and relay 2 energizes in a circuit 12, 13, 38, 39 and the sequence switch is driven to sub-normal position 18 in which it waits until both the other cords A, B of the sub-group to which the used cord belongs are moved off normal, at which time it returns to normal. The relay 6 is arranged to open the metering circuit (normally over contact 35) to prevent metering on a fault call. The above arrangement mav be adapted to release the register-controller and give a signal in the event of undue delay between dialled digits. A timing device as described in Specification 239,630 may be provided to actuate an alarm if the register-controller fails to release.