Asterisk is a complete PBX in software. It runs on Linux, BSD and MacOSX and provides all of the features you would expect from a PBX and more. Asterisk does voice over IP in many protocols, and can interoperate with almost all standards-based telephony equipment using relatively inexpensive hardware.

Asterisk is both an open source toolkit for telephony applications and a full-featured call-processing server in itself. It can be a standalone system, or used as an adjunct to a previously existing PBX or Voice Over IP (VoIP) implementation. It can be software only, moving calls around via IP, or it can have a variety of hardware interfaces to directly tie in with existing TDM (Time Division Multiplexing) equipment. Asterisk is a Computerized Telephony Integration platform, which just happens to have a number of very useful input/output channels through VoIP.

Def. DIGIUM @ www.digium.com | www.asterisk.org