Unified Communications Server
Java VoIP Softphone (SIP) (replaced by jfPhone)
Online Internet Phone Call Center Software For Telesales Team
H.323 Gatekeeper for VoIP and videconferencing
Samples and wrappers around the Bria desktop API
Chat with your friends everywhere, whether you are in space or on eart
A suite of open-source tools and frameworks for creating SIP apps