SIP, the Session Initiation Protocol, is a control protocol for multimedia sessions. Although most SIP software and hardware is designed for the simple case of VoIP telephony, SIP is actually a ...

Ubiquity develops SIP-based communications software to service providers, ISVs (independent software vendors) and OEMs (original equipment manufacturers) around the world. SIP technology, for instance ...

There is a way to make calls free all the time. The other party just needs to belong to the same SIP service as you do. SIPs, or session initiation protocols, are a variety of VoIP — Voice over ...