CallWeaver is a community-driven, vendor-independent, cross-platform,
open source, PBX software project (formerly known as OpenPBX.org).
It was originally derived from Asterisk. Now it supports analog and
digital PSTN telephony, multi-protocol voice over IP telephony, fax,
software-fax, T.38 fax over IP and many telephony applications such as
IVR, conferencing and callcenter queue management.
