3CX

3CX is the developer of 3CX Phone System, the only software-based PBX for Microsoft Windows, which not only replaces proprietary phone systems, but also delivers a complete Unified Communications solution. 

3CX is an open SIP standard software based IP PBX, which can be integrated with other applications running on Windows and delivers a future proof, best of breed phone system.

3CX includes a full suite of Unified Communications features without the need for additional downloads, add-ons or purchases. Integrated, WebRTC-based video conferencing via an open-standards browser or through the iOS/Android apps allows for face-to-face meetings to take place wherever you are. Productivity boosting features such as Presence, corporate chat, whiteboard, screensharing and more, allow employees to collaborate better and work more efficiently.