Asterisk

Asterisk is free software that transforms a computer into a communication server. Asterisk lets you build applications like PBX, VoIP gateway, IVR and ACD.

Free Open Source Mac OS X Windows Linux

FreeSWITCH

FreeSWITCH is a scalable open source cross-platform telephony platform designed to route and interconnect popular communication protocols using audio, video, text or any other form of media.

Free Open Source Mac OS X Windows Linux BSD

3CX Phone System

3CXPhone is a free VoIP phone available for Windows, iPhone or any Android based smart phone such as Google Nexus, Sony Xperia, Motorola Droid or Samsung Galaxy.

Freemium Windows Android iPhone

Yate - Yet Another Telephony Engine

Yate is a softswitch (concept of separating the network hardware from network software). It supports VoIP protocols: H.323, SIP, IAX1, IAX2, RTP. For the plain old telephony systems (PSTN) it supports ISDN BRI and PRI.

Free Open Source Linux

Wazo

Wazo is a unified communications platform based on Asterisk and focused on extensibility.

Free Open Source Mac OS X Windows Linux Self-Hosted

XiVO

XiVO is an IP-PBX, a unified communications platform that connects phones on a local or private network with other networks such as public landlines and mobile...

Free Open Source Mac OS X Windows Linux

sipXecs

A SIP based implementation of a PBX / unified communications system.

Free Open Source Linux

Kamailio

Kamailio® (successor of former OpenSER and SER) is an open source SIP server released under GPL, able to handle thousands of call setups per second. Among features:...

Free Open Source Linux

VoipSwitch

VoipSwitch is a SoftSwitch System with routing and billing, with SIP protocol support (in older versions also H323). Basic package includes softswitch app, IVR app...

Commercial Windows

Starfish PBX

Starfish PBX aims to be an open source alternative to Digium’s Switchvox. The goal is to have a software equivalent to which we can add additional functionality like: ...

Free Open Source Linux

Ozeki Phone Systems

Ozeki Phone System XE is a Software PBX telephony platform for Windows. Ozeki enables your applications to connect PBX and access IVR, Webphone, SMS sending, 3D video...

Commercial Windows

MiRTA PBX

The most advanced interface for managing Asterisk PBX with Multitenant and Realtime capabilities.

Commercial Linux