Asterisk is a complete telephone system ( PBX) . It runs on many different platforms and provides all of the features you would expect from a commercial PBX and more. Asterisk does voice over IP in four protocols, and can interoperate with almost all standards-based telephony equipment using relatively inexpensive hardware.

Asterisk provides Voicemail services with Directory, Call Conferencing, Interactive Voice Response, Call Queuing. It has support for three-way calling, caller ID services, ADSL,  IAX, SIP and H.323 (as both client and gateway)

A single (or multiple) VOIP provider(s) can be used for outgoing and/or incoming calls (outgoing and incoming calls can be handled through entirely different VOIP and/or telco providers)

OCM can build , install and support a telephone system specifically designed for your businesses needs.