Java VoIP Softphone (SIP) (replaced by jfPhone)
Accent interfaces and controls systems through goals and policies
H.323 Gatekeeper for VoIP and videconferencing
Java VoIP/SIP PBX system (replaced by jfPBX)
Optimized and cross platform SMPTE 2022 FEC library in C, Python, Java
The OZEKI VoIP Service Checker allows you to check VoIP services.
Web interface for OpenSIPS
C++ SIP stack based on Chrome source code