The SIP Center - A portal for the commercial development of SIP Session Initiation Protocol / Training And Tools / User Agents, Source Code

User Agents, Source Code

SIP Client Software, User Agents, Source Code

See also:

Asterisk - SIP compliant open source linux PBX

CNR SIP Phone for free from Center for network research Prince of Songkla University,Thailand.

Columbia SIP User Agent (sipc)
sipc is a SIP user agent that can be used for Internet telephony calls, multimedia conferences, instant messaging, shared web browsing, desktop sharing and network appliance control. It supports a range of media types, such as audio, video, text and white board, and can be extended easily to additional media types. sipc runs on a range of platforms: Windows 95/98/NT/2000/XP, Linux and Solaris.

EarthLink SIPshare
EarthLink SIPshare, a simple, SIP-based proof-of-concept content sharing application, demonstrates the viability of SIP as a protocol over which peer-to-peer (P2P) applications other than the well-known voice and video cases may be implemented.

Enterprise Interaction Center (EIC) - Interactive Intelligence is now offering a free version of its Microsoft-based, SIP-ready IP PBX communications software.

Gizmo Project - A developer of a SIP-based "softphone" that allows people to make PC-to-PC calls for free. Gizmo also includes IM, free customizable voice-mail, free conference calling, and more. It's a great example of a client application using and promoting all the good things about the SIP standard.

Kiax - Kiax is an IAX client application (a so called Softphone) which allows PC users to make ordinary VoIP calls to Asterisk servers, the same way as they do it with their hardware telephone. It aims to provide a simple and user-friendly graphical interface and desktop integration for calling, contact list, call register management and easy configuration. That is - a simple to use IAX Client.

LinPhone is an open source (GPL) SIP video phone with a Gnome and a console interface. It supports the essential SIP features and many codecs (speex, gsm, ilbc, g711, mpeg4, h263-1998 and theora ). It is written in C.

Microsoft Portrait
Microsoft Portrait is a research prototype for mobile video communication. It supports .NET Messenger Service, Session Initiation Protocol and Internet Locator Service on PCs, Pocket PCs, Handheld PCs and Smartphone. It runs on local area networks, dialup networks and even wireless networks with bandwidths as low as 9.6 kilobits/second.

NetZero - Use your NetZero Voice software on your computer to talk to anyone, anywhere in the world. Talk as much as you want, anytime you want for free*
(*See web site.)

SCS-Client-Seimens
The SCS-Client is a powerful multimedia application that solves all of the PC-user's communication needs by providing a wide range of communication features. The convergence of presence-based features and multimedia communication (audio, video, chat, instant messages and document file transfer) into a single application brings the idea of "polite telephony" into life and gives the user the right tool to exploit the possibilities of both the "old" and "new" telecommunication worlds.

SIP COMMUNICATOR is a Java SIP User Agent built on top of the JAIN-SIP-RI and JMF. Currently SIP COMMUNICATOR supports audio/video sessions over IPv4 and IPv6. Features planned for the near future are: a J2ME port, presence and instant messaging, mobility.

Siptrex Source Code - Includes both java and class files for all net.siptrex and jain packages and class files for the required antlr and gov.nist packages. also includes win32 bat files for compiling and initialisation file examples.

Speak Freely is a 100% free Internet telephone

Sofia-SIP Library - Sofia-SIP is an open-source SIP User-Agent library, compliant with the IETF RFC3261 specification. It can be used as a building block for SIP client software for uses such as VoIP, IM, and many other real-time and person-to-person communication services. The primary target platform for Sofia-SIP is GNU/Linux. Sofia-SIP is based on a SIP stack developed at the Nokia Research Center.

Twinkle - Twinkle is a soft phone for your voice over IP communcations using the SIP protocol. You can use it for direct IP phone to IP phone communication or in a network using a SIP proxy to route your calls.

Zultys Technologies - LIPZ4 Free Linux softphone