PURPOSE: To realize the miniaturization and the economization of a stand-by power unit by letting the supply characteristic of a circuit current in a subscriber's circuit have to two kinds, at least, of feeding characteristics.
CONSTITUTION: A relay R is connected to a control line CNT, and when power supply from the outside is supplied normally, the circuit current is supplied through feeder resistance Rf1, Rf2, and when the power supply from the outside is disconnected, the relay R operates, and contacts r1, r2 are switched to an auxiliary feeder resistances Ra1, Ra2 side. At that time, by setting the auxiliary feeder resistance larger than the feeder resistance, the circuit current can be made small. Accordingly, when the power supply from the outside is stopped, the circuit current supplied to terminal equipment is reduced, and the capacity of the stand-by power can be made small. Thus, the advantage of the miniaturization and the economization of a device can be obtained.
ISHIZAWA AKIRA
IHARA KENICHI
| JPS61163796A | 1986-07-24 |