Patent GB-343517-A (GB)
Title: Improvements in circuit arrangements for toll telephone systems with repeaters
IPC: H04M3/40
Filed: 1929-11-20
Abstract: 343,517. Manual exchange systems. STANDARD TELEPHONES & CABLES, Ltd., Columbia House, Aldwych, London. -(Dorgelo, J. and Rijn, K. C. van; 18, Rue Boudewyns, Antwerp, Belgium.) Nov. 20, 1929, No. 35476. [Class 40 (iv).] In a repeater system employing, at a toll exchange, separate line operator's and repeater operator's positions, line operator's connecting circuits and repeater cord circuits, a transit trunk is provided between the two positions over which the completed connection is supervised. The plugging in of a repeater cord circuit automatically connects a repeater in the connection. In Fig. 1 only one wire of the speaking circuit is shown. When a call arrives over CgT the operator at the line position LP selects either manually or by means of an automatic switch a free transit trunk TT to the repeater position B over which the number of the required circuit is passed. The plugs CA, CP are inserted in the jacks of the calling and wanted circuits and as key RPK2 has been operated by the line operator, relays BR2 and R2 energize, connecting the called circuit with the transit trunk. When the called party replies, the line operator depresses key RPK1, releasing COR1 and allowing BR1 and R1 to energize. R3, R4, R5 pull up connecting the repeater Rr in the connection and connecting the transit trunk TT to the monitoring circuit of the repeater. To reduce the gain of the repeater, key RGK is depressed which allows R9 and R10 to energize, the latter relay locking up and operating the gain reduce circuit in known manner. By restoring key RPK1 the repeater may be cut out and the connection extended over TT. When either party clears the operator at the local exchange rings on the circuit. If the repeater is still in circuit relay R6 or R7 responds energizing R8 and connecting flashing current to flash lamp CLL. The line operator clears lighting lamp CL in the repeater cord circuit whereupon the repeater operator withdraws the plugs CA, CP to release the connection. The line operator can set up a series of connections over the repeater circuit without the aid of the repeater operator. In the embodiment shown in Fig. 2, the line operator connects the calling and called circuits with a line circuit LC and communicates with the repeater operator to connect a double plug repeater circuit with the calling and called lines. When the line operator plugs into the circuits relays SLR1 and SLR 2 energize and, when the repeater circuit has been connected, relay DR pulls up energizing SRF, SRB, LVR1, LVR2. CLR and SR2. The repeater RP is thus connected in the circuit and the monitoring windings M of the repeater are connected to the line operator's position. The receipt of ringing current over either line energizes either RRF or RRB releasing HR and energizing RR to connect ringing to light the line operator's circuit lamp. The line operator can ring on either line by throwing the relative key R, of which only one is shown, and can speak over the toll circuit after operating key T and a splitting key (not shown). The removal of either plug releases the repeater and connects the line circuits directly to the line operator's multiple.