Issabel PBX - Unified Communications
VICIdial Contact Center Suite
The most affordable CRM system according to Capterra
Open source CSTA library
Unified Communications Server
Unified Communications System - PBX System
This is a PBX dashboard showing the peer,queue,agent at real time
Proximus Forum 700 pbx dial number management
A Better PBX For Your Business
Enterprise telephony recording and retrieval system
Java VoIP/SIP PBX system (replaced by jfPBX)
vTiger Freeswitch PBX Integration
Respins of various open source PBX projects