HP VCX V71xx Gateway Series Voice over IP gateways help enterprises transition to IP communications using a cost-effective strategy that aligns financial considerations with performance needs. The gateways lay the foundation for a successful deployment of Session Initiation Protocol (SIP)-based applications, and enable interoperability between a converged IP network and legacy equipment - including PBXs, the public switched telephone network (PSTN), analog phones, and fax machines. The HP VCX V7122 digital gateways provide all necessary functions and protocol support for handling voice calls between traditional circuit-switched phone networks and an IP network.