Home telephone exchange

Abstract

A telephone system used in the home which provides special services such as intercom, paging, remote turn on or off of power contacts, audio monitoring, etc. A central control is interposed between the subscriber's line and the local wiring in his home, or is connected in parallel thereto. One or more telephone subscriber sets are plugged into the wiring as usual, contacting the tip and ring leads. In the present invention, remote special service circuits are plugged into the telephone line, contacting the remaining two conductors, referred to below as the black B and yellow Y leads. Each of the remote special service circuits has a specialized function, e.g., a typical circuit will have a speaker, an amplifier for driving the speaker, and a circuit for enabling the amplifier and connecting it across the black and yellow leads once an address has been received on the black and yellow leads. Preferably, a housing containing this type of module has a socket into which a subscriber's telephone set can be plugged, and the circuit itself is connected to the local telephone line, connecting the telephone set directly or via a switch to the tip and ring leads and connecting the amplifier and enabling circuit to the black and yellow leads. Each telephone set thus will have a local speaker associated with it. However in a typical installation there could well be special service circuits of the latter type connected to the local telephone line without having a telephone set connected into it, or located adjacent thereto.