KPhone is a SIP (Session Initiation Protocol) user agent for Linux,
with which you can initiate VoIP (Voice over IP) connections over the
Internet. It supports Presence and Instant Messaging, and to some extent
also video calls between two hosts.

The original KPhone was written by Billy Biggs, modifications made by
Pekka Raisio, Jouni Vuorela and Juha Heinanen at Wirlab.