Patent GB-262182-A (GB)
Title: Improvements in or relating to automatic & semi-automatic telephone systems
IPC: H04Q3/00
Filed: 1925-09-04
Abstract: 262,182. Siemens Bros. & Co., Ltd., and Patterson, W. G. Sept. 4, 1925. Automatic exchange systems.-In the system described, the release relay B of a first code selector, Fig. 1, is held initially in a circuit l1, k4, P1 over which the dialled digits are repeated by relay L to the A-digit switch and register controller and the interruption of this circuit at the register-apparatus and the consequent relapse of relay B is used to release the register-apparatus and give an alarm if dialling is delayed. The invention is not confined to register controller systems, and according to the Provisional Specification the release relay may be held in a circuit running through a subsequent selector. Selection and setting of A-digit switch. When ,the first code selector is seized, line relay L, release relay B, impulse relay A. and change-over ,relay C pull up and a circuit b4, c4, C1, k1, c3, k6, dm is made for magnet DM which drives the switch A<1> - - D<1>, P<1> in search of an A-digit switch. When one is found, relay K being no longer short-circuited, connects relay A over wipers A<1>, B<1> and bridge in the A-digit switch to ground on h2, completes the impulsing circuit over PI, and locks up. Relay AA energizes release relay BA and change-over relay CA (i), dialling tone is sent back from DS, and the A- ,digit is repeated over CA(2) to the vertical magnet VM. Springs n<1> - - n<3> change-over at the first step disconnecting CA(1) and at the end of the digit relay CA falls back, energizing the rotary magnet RM, which at the end of the stroke closes rm and energizes and is released by stepping relay C. If the line is busy, relay HA is short-circuited and relav G on falling back re-energizes magnet RM. When an idle line is found, relay HA pulls up to battery ahead, switches through, and locks itself to ground returned to the register controller, and relays AA, BA fall back. Operation of register controller. Impulse relay AD pulls up in series with release relay B in the first code selector, and energizes release relay BD. In due course the register controller sends out trains of impulses over the wires a, b. First code selector. Relay A repeats the first translated digit over C(2) to magnet VM. Springs n1 - - n3 change over on the first step, disconnecting C(1), and the relapse of relay C at the end of the digit releases relay A and energizes the rotary magnet RM. At the end of the stroke contact rm connects relay A to the test wiper, and if the line is busy relay A releases the rotary magnet and then falls back to reenergize it. When an idle line is found, relay H is no longer short-circuited and pulls up in series with relay A when contact rm closes, extends the a, b, and a wires, releases the magnet, and locks up. Completion of connection; metering, When the register controller completes its operation, relay K is released, and sole control of relay B is restored to the calling subscriber. When the called party replies polarized supervisory relay D completes a circuit for DA(1) including wire 10 which is connected to battery at intervals. Relay DA locks up over DA(2), db2, da2. After an interval wire 10 is disconnected and' wire 11 receives a battery impulse which energizes relay DB(1) provided relay D and therefore relay DA are still energized. Relay DB disconnects winding 1, 2 of relay DA (which however holds up over DA(3), DB(1), while the wire 11 is energized) and sends a metering impulse from da2 to wire m. At the end of the impulse, relay DA is released but relay DB remains locked up in series with relay H. While relay DA is operated ground at da3 is connected to back contact l1 to prevent release of relay B if the subscriber hangs up. Normal release of register apparatus. When the register controller has sent the final digit, relay BD is released and relay DD is temporarily disconnected from the c-wire, and when as a result the switching relay HA, Fig. 2, falls back, relay AD is released and release magnet MM is energized. Release of talking chain and hunting switch. When the calling party hangs up, relays L, B, H fall back and the release magnet MM is energized and at mm keeps release relay B disconnected until the switch has been restored. A homing circuit D<1>À h6, dm is made for the hunting switch. If the call is to a manual board, battery is connected to wiper A<0>, and when the subscriber releases relay L, relay MH pulls up over h5, d1. db4, and holds relay B. If the call is released before an A-digit switch has been found (relays A, C being energized) the relapse of relay L releases relay A which energizes the vertical magnet over C(2) in parallel with relay M which locks up, stops the hunting switch, and disconnects relay K. The relapse of relay B shortly afterwards completes the release. Premature dialling. Relay A repeats the digit to magnet VM and relay M disables the hunting switch as described in the preceding paragraph. At the end of the train, relay C completes the rotary circuit. and since the connection to the test wiper is replaced by a local ground over b4, m6, m5 the switch moves to 11th terminals. relay H pulls up, and continuous tone is sent back from NU. Delay in dialling. Release relav BA in the A-digit switch connects relay TP(1) to a time pulse 12 over normal contacts of a vertical wiper E. At the first impulse, relay TP locks itself and connects relay MA(2) to a second time pulse 13 which is grounded a suitable interval after the impulse in 12. If the subscriber does not dial in this interval relay MA opens the impulse wire to release relay B in the first code selector but holds relay AA in parallel after an interval to allow the disconnection of wire p at the first code selector, relays MA, AA, TP fall back, and the vertical magnet takes a step. An instant later, relay BA falls back and energizes the release magnet MM. Meanwhile the relapse of relay B energizes relay M which cuts off relay K, whereupon wiper PI is disconnected, relay B pulls up again, and relay A pulls up over the loop and energizes relay C. This condition persists until the switch is released by the subscriber or by an attendant. If the subscriber dials at this stage he receives NU tone as in the case of premature dialling. In case the subscriber pauses unduly after sending in the office code, the register controller sends out the routing digits and is then released by the operation of relay MD which releases relay B in the first code selector. Relay M pulls up, cuts off relay K, and short-circuits relay H, which releases the switches ahead. Relay B is re-energized over k4 and energizes the rotary magnet which drives the switch to 11th terminals to cause NU tone to be sent back as in the case of premature release. Accidental impulses prior to dialling. If the A-digit switch is stepped to its first level, relay MA is energized by the vertical wiper E and the relapse of relay CA energizes the release magnet, which holds relay MA at mm until release is complete. Relay G meanwhile disconnects the rotary magnet, the circuit of which is open also at ma2. Exchange attendants' signals &c. Lamp CSH glows in the case of abnormal operation when relay M pulls up, and also, when the called party hangs up first. According to the Provisional Specification, the provision of the release magnet contacts mm in the circuit of relav B enables a trouble man to release the first code selector by pressing on the release magnet armature. Busy signalling arrangements ; statistical metering. If the A-digit switch finds all register controllers busy, 11th terminal springs s1 - - s3 change-over and relay MA(1) pulls up. over rm, locks itself, and cuts the rotary circuit and busy tone is sent back from BB. Relay AA remains energized since relay HA is unable to pull up over the statistical meter which is operated over ba6, ma4. If the first code selector is unsuccessful. 11th terminal springs s1 - - s3 change over, relay H which is no longer short-circuited releases the rotary magnet and locks up, and busv tone is sent back from BB. If the wanted line is busy, a tone signal is sent back together with busy flash, which is repeated by relay D.