If you buy an additional handset (Model CS2052), it will not work automatically.

“The CS2051 is nearly identical to the CS2011 and CS2111 series. If you can’t find the CS2051 manual, those manuals cover the same setup and button functions.”

To completely deregister all handsets (for example, if moving to a new account):

He approached it. The small LCD screen, normally blank, was glowing. It displayed a message:

: Verify that the telephone line cord is securely connected to the base and the wall jack. JustAnswer Important Safety Note