Patent GB-440348-A (GB)
Title: Improvements in or relating to call-recording arrangements in telephone or like systems
IPC: H04M15/04
Filed: 1934-06-26
Abstract: 440,348. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd., 63, Aldwych, London.-(Hatton, W.; 4, Rue Boudewyns, Antwerp, Belgium) June 26, 1934, No. 18831. [Class 40 (iv)] Calls which are completed automatically through a central exchange in a rural area are recorded by common apparatus which makes a printed record of the numbers of the calling and called subscribers and of the duration of the call. As shown, the recording-apparatus is associated with each incoming junction at a rural main exchange, and a junction is held after the subscribers hang up to permit impulses representative of the calling party's number to be received from identifying apparatus at the originating exchange. A.C. impulsing over the test wire is employed for this purpose in the case of three-wire junctions or over a simplex circuit in the case of two-wire junctions. When the junction is seized, relays A, B energize and the digits of the wanted number other than the first are transferred from the register-controller RC at the originating exchange to a registercontroller IR associated with the incoming end of the junction by revertive-impulsing over the b wire, the impulses being transmitted at the same time by way of a thermionic valve V3 to relay I which repeats them to the printer PR. Since the numbers of impulses are complementary to the digits of the wanted number, the number-wheels of the printer must be arranged in such a way that the actual digits are printed. The first digit is determined by the identity of the junction to which the printer is individual. Relays C, Sa then pull up, disconnecting the printer from the b wire. Upon the reply of the called party, relay S energizes followed by T, P and Q. During conversation impulses from a clock circuit CL are delivered to the printer which marks the duration of the call. When the calling party hangs up, the relapse of relay As causes relays D, E, F, G to energize in turn and D, E, F then to release, effecting a momentary operation of relay N to send a long impulse of A.C. of 1000 cycles over the c wire. This is received via condensers C1, C2, by a valve V1 and brings about the operation of relays S, Sa, La, to start the finder P. When the calling line is reached, A.C. passes via condenser C3 to a valve V2, operating relays Tr, Ta. On the cessation of the A.C. impulse relay Tr falls back and connects up Na, Cu1, Cu2 and Sr to initiate impulsing, the c wire being now connected to the front contact of relay Is, the armature of which is connected to a source of A.C. of 400 or 450 cycles. A wiper of the finder P corresponds to each digit of the calling party's number, and all the terminals corresponding to the same digital value are strapped together and connected to the appropriate terminal of the sending switch S1. A sequence switch S2 renders the wipers of the finder P effective in turn. Relays Nm1, Nm2, each controlling the circuit of the other, deliver impulses to relay Is and to the magnet of the switch S1, so that A.C. impulses are sent over the c wire until the switch S1 reaches a position marked by the finder P, when Tu Ot pull up and open the circuit of Nm1. The switch S1 goes home and Tu, Ot, fall back, sending an impulse to step the sequence switch S2 and starting the sending of the second digit. After all the digits have been sent, the switch S2 goes home and La unlocks and releases Ta, Sa. The impulses are received via the valve V3 by relay I which repeats them to the printer PR. When all the digits have been received, relay T is unlocked and relay B is disconnected to release the junction. If the identifying circuit is in use when the 1000 cycle impulse is sent, it produces no effect. A thermostatic relay Th is connected up by G and operates after 20 seconds, connecting up Sm and releasing G, so that relays D, E, F, G, are effective as before to send a second 1000 cycle impulse. Relay Im energizes and disconnects Th, which after a further 20 seconds falls back, and short-circuits T to release the junction if this has not already taken place. Instead of recording the calling party's number after conversation, it may be recorded during the conversation, A.C. impulse being sent over the c wire or over a simplex circuit in the manner described in Specification 435,155, the time impulses being stored until the end of the conversation. The Provisional Specification describes another arrangement in which the recording apparatus is situated at the originating exchange, and the called party's number and the duration and time of the call are transmitted thereto from storage apparatus at the rural main exchange at the end of the conversation. Specifications 150,727 and 310,120, [both in Class 40 (iv)], also are referred to.