freepbx - FreePBX is a web-based open source GUI that controls and manages Asterisk (PBX).

Genesys - Genesys provides omnichannel customer experience and contact center solutions in the cloud and on-premises.

FreeSWITCH - FreeSWITCH is an open-source media application designed to support popular protools such as SIP and WebRTC and provides a platform to develop voice and video applications.

Voiceglue - Our overall goal is to provide a full-featured integration of open source telephony environments...

Asterisk - An open source telephony switching and private branch exchange service for Linux.

Aspect Prophecy - Aspect Prophecy is a powerful, entirely standards-based platform for speech, IVR, and SIP VoIP...