How to register / deregister a telephone handset.
The supplied handset and base unit are preregistered. If for some reason the handset is not registered to the base unit, or if you purchase an additional handset, this answer will show you how to register the handset.
How to set up the telephone's date and time.
The Date and time is automatically displayed by signals that it receives from your telephone provider. However if for some reason it is incorrect you can manually set the date and time.
Panasonic Telephone Cell Phone Compatibility List
In order to pair your mobile device to Panasonic DECT phones, it MUST support HFP (Hand Free Profile). Listed here are Panasonic Telephones and compatible cell phone brands and models that have been tested. If your Cell phone is not listed, confirm with the mobile device manufacturer that it supports HFP (Hand Free Profile).