Re:Toxic – A distributed, secure, command-line based instant...
by Jfreegman on Wednesday February 11, 2015 @08:45PM
(#9036881)
Toxic has 1 on 1 audio chats, and GUI clients such as uTox and qTox additionally have group audio, as well as 1 on 1 video. Both clients are usable, though I would personally recommend qTox.
[0] - https://tox.im/