This menu displays known SIP extensions that are currently unregistered.  This menu is supported from Release 10.1.

• It may take several minutes for a previously registered extension to become listed as unregistered.
• Unregistered does not include temporary extensions (those that only exist as dynamic extensions whilst registered rather than as configured extension entries).
• DECT extensions don't show as unregistered.
• No extension status screen is available for unregistered extensions.
• Centralized branch extensions show as unregistered during normal operation.