Java wrapper for the popular chat & VOIP service
Java VoIP Softphone (SIP) (replaced by jfPhone)
Accent interfaces and controls systems through goals and policies
Universal Framework to audit Voip protocols's security
Optimized and cross platform SMPTE 2022 FEC library in C, Python, Java
The OZEKI VoIP Service Checker allows you to check VoIP services.
C++ SIP stack based on Chrome source code