![]() | The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. (July 2013) |
A sound-powered telephone is a communication device that allows users to talk to each other with the use of a handset, similar to a conventional telephone, but without the use of external power. This technology has been used since at least 1944[1] for both routine and emergency communication on ships to allow communication between key locations on a vessel if power is unavailable.[2] A sound-powered phone circuit can have two or more stations on the same circuit. The circuit is always live, thus a user begins speaking rather than dialing another station. Sound-powered telephones are not normally connected to a telephone exchange.