Asterisk: Open Source Telephony Platform An open source communications platform, Asterisk® is a complete IP PBX in software. It runs on a wide variety of operating systems including Linux, Mac OS X, OpenBSD, FreeBSD and Sun Solaris and provides all of the features you would expect from a PBX. Asterisk is free software that transforms a computer into a communication server. Asterisk lets you build applications like PBX, VoIP gateway, IVR and ACD. in Work > BP: Communications > VoIPwith asteriskcommunicationspbxplatformsourcevoipby 11 users