VoIP SIP and SKINNY quality analyzer and packet / audio recording tool
Open source Fax server software for inbound / outbound internet Faxing
Unified Communications Server
High performance, production quality STUN server and client library
VoIP/SIP Autodialer
SIP softphone
H.323 Gatekeeper for VoIP and videconferencing
Callflow Sequence Diagram Generator
A command line utility for remote controlling Polycom VVX IP phones
Java VoIP/SIP PBX system (replaced by jfPBX)
Simple web interface for mapping CDR from VoIP provider to Asterisk
An administration web interface for Mumble VoIP servers in PHP
Simple and efficient tool for SIP trace filtering