FreeDV is a GUI application for Windows and Linux that allows any SSB radio to
be used for low bit rate digital voice.
Speech is compressed down to 1400 bit/s then modulated onto a 1100 Hz wide QPSK
signal which is sent to the Mic input of a SSB radio. On receive, the signal is
received by the SSB radio, then demodulated and decoded by FreeDV.
FreeDV was built by an international team of Radio Amateurs working together on
coding, design, user interface and testing. FreeDV is open source software,
released under the GNU Public License version 2.1. The FDMDV modem and Codec 2
Speech codec used in FreeDV are also open source.