VaxTele SIP Server SDK ([[Software Development Kit]]) is a complete development toolkit, which allows software vendors and [[Internet Telephony Service Providers]] (ITSP) to develop [[SessionSIP Initiation ProtocolServer]] and (SIP) [[Session Initiation Protocol]] based VoIP serverssystems for [[Microsoft Windows]] to install computer to computer voice chat, chat rooms, [[IVR systems]], [[call center services]], calling card services, dial/receive computer to PSTN ([[Public Switched Telephone Network]]) and mobile phone calling services.
