A TELEPHONE LINE SWITCH

摘要

A telephone subset line switch (Fig. 1), comprising input terminal means (3, 4) for coupling to the line terminals of a telephone subset circuit, and output terminal means (1, 2) for connection to the transmission circuit of the subset circuit, a first semiconductor switch means (TR 1) having a controllable conductive path serially connected between a first terminal (3) of the input terminal means and a first output (1) of the output terminal means, a second semiconductor device (TR 3) having a controllable conductive path connected between the control element of the first semiconductor switch (TR 1) and a second terminal (4) of the input terminal means, the second input and second output terminals being common, and whose control element forms a first control input for coupling to control means associated with the transmission circuit for controllably switching the telephone subset's loop current circuit.