A type of AllCall registration feature, the use of which combines the registrations for incoming and outgoing calls for the current terminal address in a single procedure. However, unlike AllCall registration, a linked registration cannot be overridden in all or in part by: (a) InCall, remote InCall, AllCall, or remote AllCall registrations by the same UPT (Universal Personal Telecommunications service) user; (b) OutCall, remote OutCall, AllCall, remote AllCall, linked, or remote linked registrations by other UPT users. The UPT user must explicitly deregister a linked registration or override it by another linked or remote linked registration.