(on Wikipedia)
http://www.teamspeak.com/

A VoIP client which is still still popular in the face of Mumble's superiority.

• AltaVoice (archive) was a mod that shows who is speaking on Ventrilo/Teamspeak.

2016-02-16 - v3.0.18.2, on Windows 10 ∞

I rarely use this, but keep it installed in case others need me on it.