pbxnsip makes SIP-based Private Branch Exchange (PBX) telephone system. The Session Initiation Protocol (SIP) is used to talk to attached devices like telephones, PSTN gateways or SIP service providers. The pbxnsip PBX is used to put the components from different vendors together to an enterprise communication system. Customers benefit from a modern feature set like mobility support and computer telephone integration and from vendor independency. pbxnsip respects the security requirements of a business critical application. Customers may run the PBX on Microsoft Windows and Linux-based servers and on embedded appliances. pbxnsip was incorporated in 2005 and is located in Massachusetts, USA.