3CX - Developers of IP PBX software for Windows. Applied Voice & Speech Technologies, Inc. (AVST) - Applied Voice and Speech Technologies, Inc. (AVST) offers SIP integrations to its flagship CallXpress unified communications platform. BaseVoice - Commercial software development company that produces PBX, router, proxy and application server software. Brekeke Software, Inc. - VoIP telephony server software manufacturer. Includes product information, free download trials, and details of the support available. miniSipServer - A cross-platform SIP server running on Windows and Ubuntu. Detailed documentation. OfficeSIP Communications - SIP based VoIP and instant messaging software for office needs. ProfInfoTech - Products include SIP server and VoIP-server with SIP and H.323 protocols support. PrimiSIP - A stateless primitive SIP server in Perl for education. OpenSIPS - A branch of the SIP Express Router project, offering an open-source SIP server.