Freeswitch/Fusion
Fusion PBX is a free and open source PBX based on Freeswitch. It optimizes the usability of GUI on the basis of Freeswitch, provides a customizable and highly flexible web interface, and makes the management of IP telephony software switch system more easier.
Fusion PBX is available for multiple operating systems and can be deployed on either Linux or Windows.
The Fusion PBX offers QR codes for portable extension, unlimited extensions, voicemail-to-email, music on hold, call park, analog lines