sips software

SipXecs is a free software enterprise communications system. It was initially developed by Pingtel Corporation in 2003 as a voice over IP telephony server located in Boston, MA. The server was later extended with additional collaboration capabilities as part of the SIPfoundry project. Since its extension, sipXecs now acts as a software implementation of the Session Initiation Protocol (SIP), making it a full IP-based communications system.
SipXecs competitors include other open-source telephony and SoftSwitch solutions such as Asterisk, FreeSWITCH, and the SIP Express Router.

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