Also known as a "personal number" service, allocates customers a "personal number", separate from the network termination port address (telephone number) of a particular telephone line. Thereby provides a universal personal telecommunications service, reachable at the same number when moving between different fixed (and mobile) lines.
The customer can then control how to handle incoming calls, for example by:
- directing calls to different network addresses at different times of day
- automatically sending calls to answering machines at specific times
- sending data calls to data terminals
- sending fax calls to fax terminals
- using other criteria, such as the caller's CLI, to determine where to terminate the call.