VoIP SIP and SKINNY quality analyzer and packet / audio recording tool
Cellular manager for mobile phones/modems
Web based system for Computer Assisted Telephone Interviewing (CATI)
Open source Fax server software for inbound / outbound internet Faxing
Unified Communications Server
High performance, production quality STUN server and client library
SIP softphone
H.323 Gatekeeper for VoIP and videconferencing
A command line utility for remote controlling Polycom VVX IP phones
An administration web interface for Mumble VoIP servers in PHP
GNU Telephony Services and Applications
Cyber-wrt pbx is embedded system in DD-Wrt router