Patent GB-258956-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/00
Filed: 1925-07-03
Abstract: 258,956. Standard Telephones & Cables, Ltd., (formerly Western Electric Co., Ltd.) (Deakin, G.). July 3, 1925. Automatic exchange metering systems.-In a system in which certain calls are set up automatically by the subscribers and others calls which have to be metered differently are set up by an operator, means for operating the meter automatically a predetermined number of times is associated with the cord circuit used in making the connection. In the system described, a sequence switch individual to the position is caused by the reply of the called party to send back the required number of impulses Establishing connection. A subscriber on calling is extended through first and second line finders A, B to a register C which for local calls controls the completion of the connection. When, however, the register is set by the two-digits denoting an operatorcall, a relay RSR becomes energized, disables at p a timing device (not shown) whereby a subscriber is normally extended to a monitoring desk m case of delay in establishing a call, marks the i terminal of the calling line in the banks of a group of special second line finders whereby the call is extended to an operator in a distant office which deals with calls of this kind from several offices, and energizes a relay CR to start these finders. Relay CR1 pulls up and energizes the power magnets P of the special finders. When the line is found, relay LTR shunts out relay CR by its low resistance winding in series with relay LMR to stop the other finders at the same time marking the first line finder non-selectable to the special second line finders. Relay LMR lights the multiple answering lamps E in the distant office. When an operator answers with the plug F, relay TSR switches the talking wires through disconnects relay LkZR and grounds the g terminals. short circuiting relay LER to release the finder B as described in Specification 187, 736. Relays LMR falls back sluggishly, extinguishing - the lamps E and substituting ground over r<1> for direct ground on the g terminals. The release of the finder B and register C releases relay LTR. In the cord circuit relay SIR pulls up. The operator calls the wanted "subscriber with the plug H. Metering. When the called party answers, relav S2R energizes the common starting relay CRM to energize the power magnet RM of a sequence switch associated with the position. In position 18 relay MR2 pulls up and locks itself and metering impulses over PMR are thus sent back in positions 1, 2 and 4, to the marginal relay SMR which repeats them to the meter SM. The latter cuts in an opposing winding as described in Specification 251,335. In position 6 relay MR1 stops the sequence switch, locks itself up and releases relay MR2. Relay SMR in operating short circuits the high resistance winding of relay TSR thus allowing relay PMR to flash the lamp SML. When the connection is taken down relays MR1, MR2 fall back and the switch RM is restored to normal by means of circuits not shown. According to the Provisional Specifications, means may be provided for operating the meter at intervals throughout the conversation.