Any of various types of acoustic apparatus, device, or instrument for conveying sound over a distance. Any apparatus which conveys sound, esp…

An instrument which produces sounds in response to an electric current, e.g. from an induction coil or telephone, esp. as developed to enable…

a telephone operated by magneto-electricity.

An apparatus in which sonorous vibrations of a diaphragm are produced by heat-rays.

Telecommunications. An instrument for transmitting sound by means of light; spec. that invented by Alexander Graham Bell and Sumner Tainter in 1880.

An instrument designed to produce or transmit sound using beams of light or other radiation. Now disused.

an instrument or apparatus designed to produce or transmit sound using beams of light or other radiation; = radiophone, n. 1; cf. photophone, n. 1.

a thermo-electric telephone.

A device which records sounds received by telephone, so that they may be subsequently replayed or reproduced; spec. one which records the sounds…

see quot. 1891.

An instrument for transmitting sound under water and recording messages so received. Obsolete. rare.

A floating device equipped to detect underwater sounds, such as sonar signals, and relay them by radio. Cf. sonar buoy n. at sonar, n. compounds 2.