A special form of the external numbers is that of the SIP URI (Uniform Resource Identifier). These numbers (usual in Internet telephony) have a format like an email address. They contain a user-specific component (user ID) and a general component (realm) that may, for example, be the same throughout a company. A "number" of this type will always start with ’sip:’ and comprises:

The user-specific part here can consist of

In the configuration of such SIP URIs, they are always prefixed with "SIP:".

A SIP URI, whether in canonical or character string form, serves in Internet telephony as the unique reference for a user, just like an external number in the public telephone network.

SwyxWare therefore allows a mapping of these SIP URIs to SwyxWare users in the same way as canonical numbers can be mapped. The SIP URIs are thus entered like the public numbers in the SwyxServer in the number/URI configuration of a trunk, and assigned to the corresponding users.

These users can then be reached by external subscribers via the SIP URI. Just as for the external numbers, one user can also be assigned several SIP URIs, under which the user can be reached from the outside world.