Patent GB-264557-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/00
Filed: 1925-09-23
Abstract: 264,557. Automatic Telephone Manufacturing Co., Ltd., and Ostline, J. E. Sept. 23, 1925. Automatic exchange systems; metering.-In a register controller system, dialled impulses are repeated by a relay LC at the first code selector FCS over a winding of a relay M which does not pull up in series with the impulse relays of the A- digit switch and register controller but is operated when these relays are short-circuited, in the case of a delay in dialling or dialling a spare code, and causes the register apparatus to be released, the next digit to be diverted to the first code selector and the latter to move to 11th terminals at the end of the digit to send a number-unobtainable tone. This relay is operated also the case of premature dialling. Means are provided for preventing metering and giving release control to an operator. A resistance r4 is provided in the meter wire MC to enable an attendant to check that the metering arrangements are in order. An observation relay plugged across the resistance responds when the metering ground 47 is connected up by the sluggish relay MD a short interval after the response of the supervisory relay D, and is short circuited by the operation of the meter. The Provisional Specification describes a similar but not identical arrangement. Specification 233,007 is referred to. Hunting switch RS and A-digit switch. When the first code selector FCS is seized, line relay LC, release relay B, impulse relay A, change-over relay C and delayed metering relay MD pull up and the hunting switch RS is started in a circuit 50, 65, 62, 32, 61. When an idle A-digit switch is reached, relay K switches through and energizes relay F which locks up, relays A<1>, B<1> pull up, and dialling tone is sent back from DT. Relay LC repeats the A-digit over the low-resistance winding of relay M and wire 60 to relay A<1> which repeats it to series relay C<1> and magnet V<1>. When the off-normal springs change over, stepping relay G<1> pulls up and on the relapse of relay C<1> the switch hunts like a group selector. When an idle register controller is found, relay H<1> switches through and relays A<1>, B<1> fall back. First code selector. Relay A repeats the first translated digit to magnet V. At the first step relay C is connected in parallel with magnet V and stepping relay E is energized. On the relapse of relay C the switch hunts in the usual way and when an idle line is found, relay H switches through and relay A is cut off. Release of register apparatus, and completion of connection. After sending the number, the register controller removes ground from 101 and relays H<1>, K fall back. The A-digit switch is released and the talking circuit is completed. Release. Preventing metering. In the case of ordinary calls, the relapse of relays LC, I, B when the calling party hangs up, completes a homing circuit 71, 48, 61 for the switch RS and unlocks relay F. After an interval to allow the switch RS to get home, relay F energizes the release magnet and removes ground from RT. In the case of long distance calls set up by an operator, relay D is not energized when the operator replies and relay MD is not released to send a metering impulse. When the calling party hangs up, relay I pulls up from 14 over the b-wire and holds up relay B. Busy signalling and statistical metering. If the A-digit switch is unsuccessful, 11th terminal springs S<2> - - S<4> change over. Busy tone and flash are sent back from BT, and a statistical meter M<11> is operated. If the first code selector is unsuccessful, springs S, S<1> change over, busy tone is sent back from BT, relay H is short circuited and relay E released. Premature dialling. Relays LC, B, A, C, MD are energized but not relay K consequently the digit is repeated by relay A to the vertical magnet in parallel with relay M which locks up, disconnects the switching relays H, K, stops the hunting switch and provides local ground 20, 27 for stepping-relay F. The selector thus moves to 11th terminals at the. end of the digit and a tone signal is sent from NUT. Accidental impulses. When a single impulse is received by the A-digit switch the change-over of springs NP which are operated only on the first level completes a circuit for release magnet Z<1>. Delay in dialling; spare codes. On the first pulse in the wire TPC after relay B<1> pulls up, relay TP pulls up its armature 96 and, when the pulse goes off, the remainder of its armatures. If dialling does not begin before the following pulse, relay G<1> short circuits relay A<1> allowing relay M to pull up over its upper winding. The A-digit switch is released and relays K, F fall back. Relay M locks up and when the subscriber dials he receives NU tone as in the case of premature dialling. The register-controller itself is arranged to control relay M in a similar manner in the case of delay in dialling or spare codes. Provisional Specification. The first code selector operates in the same way as that described above with the following exceptions. The impulse circuit winding of the forced release relay M is short-circuited by a sluggish relay F which pulls up at the first impulse of each digit dialled. The supervisory relay D grounds the meter wire directly. Release control is given to an operator as follows. Relay A remains locked up over 40, 12 since relay D is not energized and when the subscriber hangs up, relay B is held up over its lower winding by relay F. The forced release relay M flashes the supervisory lamp. There is no means for guarding the relay group while the non-numerical switch is being restored.