KPhone is a SIP (Session Initiation Protocol) user agent for Linux, with which you can initiate VoIP (Voice over IP) connections over the Internet. KPhone requires KDE (K Desktop Environment) or at least various libraries from the KDE package. KPhone also requires the OpenSSL libraries to be present in the system. KPhone has been somewhat tested on Red Hat 7.2 and 7.3, Slackware 8.0, SuSE 8.1 and Debian. Requirements on each distribution vary according to the installation layout.