Issabel PBX - Unified Communications
VICIdial Contact Center Suite
Open source CSTA library
The most affordable CRM system according to Capterra
Unified Communications Server
This is a PBX dashboard showing the peer,queue,agent at real time
Enterprise telephony recording and retrieval system
ERP, IP PBX, Accounting, CRM, Time tracking, and etc.
Java VoIP/SIP PBX system (replaced by jfPBX)
vTiger Freeswitch PBX Integration
Respins of various open source PBX projects