freepbx - FreePBX is a web-based open source GUI that controls and manages Asterisk (PBX).
VoIP Softswitch Solution - VoIP Softswitch Solution is a smart VoIP software that provides billing, call management, advance routing suctions, and billing management.
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.
Voyced - Voyced is an all VoIP provider that provides businesses with the ability to streamline their communications with virtual telephone numbers, services, and more.
Asterisk - An open source telephony switching and private branch exchange service for Linux.
BVoIP - BVoIP allows to easily add Cloud & On-Premise VoIP PBX to the product offering without having to re-invent the wheel or add another layer to the daily operations..