Acoustic Coupler

In telecommunications, the term acoustic coupler has the following meanings:

1. An interface device for coupling electrical signals by acoustical means—usually into and out of a telephone instrument.
2. A terminal device used to link data terminals and radio sets with the telephone network.

The link is achieved through converting electric signals from the phone line to sound and reconvert sound to electric signals needed for the end terminal, such as a teletypewriter, and back, rather than through direct electrical connection.