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..

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

Windstream Holdings - Windstream Holdings is a scalable cloud-based business phone solution that provides complete and unified communication applications to businesses of all sizes.

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.

Loop Communications - Loop Communications provides hosted VoIP business phone systems to small businesses and mid-sized companies.

FusionPBX - FusionPBX is an open source FreeSWITCH GUI.