FreePBX

Deployed in over 200 countries or states, FreePBX is a web-based open source GUI (graphical user interface) that controls and manages Asterisk (PBX), an open source communication server. It comprises a community of developers and contributors who aim to make phone system software functional and easy to use. Sangoma Technologies is the principal corporate sponsor, while FreePBX also has strong relationships with Digium and the sponsors of Asterisk.