VoIP SIP and SKINNY quality analyzer and packet / audio recording tool
Browse on Tor/i2p, Anon p2p Chat / FileTx, Conf / Video VoIP
open5g is an open source implementation of the 3GPP 5G specifications.
H.323 Gatekeeper for VoIP and videconferencing
SIP Video Multiconference Media Server with WebRTC support.
GNU Telephony Services and Applications
ss7mon an SS7/SIGTRAN signalling monitor
TAPI Phone Monitor for Windows
GSM L1-L3 stack with SIP network interfaces