sip communicator

TekSIP is a SIP Registrar and Stateless SIP Proxy for Windows.

Free Softphone for Windows. Works with any SIP/ VOIP provider and SIP PBX

Free enterprise communicator supporting instant messaging, chats, VoIP and video

Universal Communicator Service that manages cross-media communication.

Softphone for PC-telephony using TAPI, CAPI or SIP plus answering machine

Auto Dialer, VOIP Autodialer, Phone Dialer, SIP SKYPE PSTN PC to Phone Broadcast

TekFax is a SIP (Session Initiation Protocol) fax receiver server runs under.

TekPhone is a SIP (Session Initiation Protocol) conference server

Command Line SIP User Agent for Windows

Freeware SIP interactive voice response system