Carterphone

The Carterphone was invented as a work-around (of AT&T's rules) to connect radio- based calls to Bell System landlines. It was the subject of the landmark 1968 FCC ruling that allowed third-party devices to be connected electrically to the Bell System network.

The Carterfone is a device invented by Thomas Carter. It connects a two-way radio system to the telephone system, allowing someone on the radio to talk to someone on the phone. This makes it a direct predecessor to today's autopatch. The connection is acoustic -- sound travels through the air between the Carterfone and a conventional telephone that is part of the telephone system.