control device of an electronic signal, dep. in france on 14 october (35).

摘要

1,267,786. Magnetostatic relays; automatic exchange systems. C.I.T. COMPAGNIE INDUSTRIELLE DES TELECOMMUNICATIONS. 14 Oct., 1970 [14 Oct., 1969], No. 48808/70. Headings H3B and H4K. A magnetostatic relay is used to control the current flowing in a pair of conductors. The relay, which is a combination of a magnetic amplifier and a transistor, has only two possible outputs, one of which is zero, and may be as described in Specification 871,623. Fig. 1 shows the relay used as a ringing stop device in a telephone network, a pair of wires A, B, being connected via transformer TR to the subscriber and having their other ends connected to an exchange (not shown). The magnetostatic relay SDE has five windings e1-e5, e1 being an optional winding for establishing the initial state of the relay. Windings e2 and e3 are control windings which are connected at Q but which are wound with opposite senses. To call the subscriber, an A.C. ringing current is passed from TA by connecting point SA to SA1 and SB to SB1, the circuit being SA1, C1, P, M, A, TR, ringing device, TR, B, N,.Q, C2, SB1. This produces an A.C. flow through e2 and e3, but does not affect the relay since the currents in e2 and e3 are equal and opposite. When the subscriber answers, D.C. current flows in a path comprising earth, R1, P, M, A, TR, subscribers instrument, TR, B, N, Q, e2, R3, -SPve/SP supply, thus producing a D.C. flow in e2 which triggers the relay SDE. This triggering actuates a device (not shown) to break connections PM, QN, and also to disconnect TA. The subscriber receives current through a circuit comprising earth, e5, R1, TR, A, his instrument, B, TR, R2, e4, -SPve/SP supply, the flow through e4 and e5 holding the relay on until the call ceases.