FreeSWITCH meta port.

FreeSWITCH is an open source telephony platform designed to facilitate the
creation of voice and chat driven products scaling from a soft-phone up to a
soft-switch.  It can be used as a simple switching engine, a PBX, a media
gateway or a media server to host IVR applications using simple scripts or XML
to control the callflow.

WWW: http://www.freeswitch.org