Remote signalling to a telephone line utilizing power line carrier

Abstract

A remote transmitting or receiving device (T/R device) communicates with a conventional subscriber telephone through available AC power wires which carry signals that may be modulations of RF carrier frequencies and which are coupled to the power wires. For example, an incoming telephone call includes signals that are detected and modulate a master RF carrier frequency which is coupled to the AC power wires at the telephone line location and these signals are coupled from the AC power wires at a remote R device location, and, demodulated and used to control an electrical appliance, motor, pump, etc. The remote T device which may be, for example, a fire detector produces signals which modulate a remote RF carrier frequency which is coupled to the AC power wires at the remote location and this modulated carrier is coupled from the AC power wires and demodulated at the telephone line location to control or initiate signals in suitable form for transmission over the telephone line. Thus, telephone calls to the subscriber's telephone line can be received at the remote location to turn on an electrical device at that location; or signals originating at the remote location initiate a telephone call and message from the transcriber's telephone line.