Matrix reference homeserver
Issabel PBX - Unified Communications
VoIP SIP and SKINNY quality analyzer and packet / audio recording tool
Browse on Tor/i2p, Anon p2p Chat / FileTx, Conf / Video VoIP
VICIdial call center optimization tools, monitoring utilities, and per
A WebRTC-Enabled Chrome Extension for Seamless Call Center
ICTCore: Unified Communications Framework for web developers
Unified Communications Server
Unified Communications System - PBX System
Java VoIP Softphone (SIP) (replaced by jfPhone)
High performance, production quality STUN server and client library
Asterisk based VoIP pbx appliance
Kazoo Live Medium. From Null to a Full Featured PBX on minutes
Accent interfaces and controls systems through goals and policies
ERP, IP PBX, Accounting, CRM, Time tracking, and etc.
Asterisk and kannel integration
H.323 Gatekeeper for VoIP and videconferencing
SIP Video Multiconference Media Server with WebRTC support.