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GNU oSIP - http://www.gnu.org/software/osip/osip.html
Implementation of Session Initiation Protocol (SIP). This library provides an interface to initiate and control SIP based sessions. |
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Linphone - http://www.linphone.org/
SIP based web phone. Supported audio codecs are G711, LPC10-15, GSM, and SPEEX. |
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Partysip - http://www.nongnu.org/partysip/partysip.html
SIP proxy server. It can operate as registrar server, redirect server and stateful proxy server. SIP is an open standard (IETF) replacement for H323. |
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http://sourceforge.net/projects/kphone - http://sourceforge.net/projects/kphone
SIP based VoIP user agent. It supports Presence and Instant Messaging. |
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http://www.minisip.org/ - http://www.minisip.org/
SIP based phone. Supports video, communication encryption and push-to-talk. |