SIP, or Session Initiation Protocol, is the basis of all next generation telephony. It is the de facto standard for maintaining a real time exchange of voice services between two endpoints over an IP connection.

SIP is the underlying open standard on which OnSIP is built.

Historically, the telephone companies used a technology called Time Division Multiplexing - which required dedicated phone lines that were run from a central office to every house and office.

With the advent of broadband internet connections, a new way of delivering phone calls was brought to market. This was called VoIP - or Voice over IP. In this case, phone calls are turned into packets of information and sent over a boradband internet connection.

Much like an email address, a SIP address serves as a locater of a person or SIP user. SIP addresses look much like email addresses. For example, our CEO has the following SIP address.