Issabel PBX - Unified Communications
The most affordable CRM system according to Capterra
Open source CSTA library
Unified Communications Server
Unified Communications System - PBX System
Proximus Forum 700 pbx dial number management
A Better PBX For Your Business
Enterprise telephony recording and retrieval system
ERP, IP PBX, Accounting, CRM, Time tracking, and etc.
vTiger Freeswitch PBX Integration