Load switching circuit coupled to telephone line - responds to telephone call signal to disconnect load current circuit for duration of telephone conversation

摘要

The circuit is coupled to a subscriber telephone wire, for switching load currents in dependence on the condition variations along the line. The incoming signals along the telephone are monitored and a load current is detected, to allow in relay in the load current circuit to be operated when a call signal and a load current occur simultaneously, for disconnection of the load circuit. The speech phase of the telephone line is monitored and combined with the load current monitoring information, to allow the load circuit to be switched back in. USE - For automatic switching out of audios appts during telephone call.