This is a VERY SIMPLE Speex VoIP client. It is not a complete VoIP application, isn't compatible with anything else (including probably future versions of itself) and does not support any form of standard protocols. It is intended only as a way to show how to use Speex in a VoIP application. To use it: On Alices machine: % speexclient plughw:0,0 bob.somewhere.net alice_port bob_port On Bob's machine: % speexclient plughw:0,0 alice.somewhere.net bob_port alice_port where bob_port is the UDP port on which bob receives and alice_port is the UDP port on which alice receives. In most cases, the two ports can be the same. Note that the clients do not even know whether they are connected or not. All they do is send/receive the audio to/from a specific port.