Info on deregistering cordless handsets
This is an information only topic which is why it is closed to posting. The following are ways proven by the users of this board to force a deregister of a cordless handset.
This works on many different makes and models of cordless handsets.
At the handset(s) do the following
*331734# followed by menu/select
The phone beeps twice, reboots and then comes back up ready to register to a new base station.
Registering to the new base station is now accomplished using the standard instructions.
For here: M/S = menu / select button (upper right)
1) M/S, scroll to SETTINGS, M/S
2) Enter *7890#
3) Scroll to TEST HANDSET, M/S
4) Scroll to NEXT PAGE . . ., M/S
5) Select REGISTER CLEAR, M/S, M/S
6) Display shows OK meaning successfully reset.
7) Use OFF button to get back to main display which will flash “to register HS...”.
Place on base, will say Registered after 15 sec or so.
Press menu, then *883247#. Arrow up, select deregister. Unplug and take the battery out for 10 seconds. Plug back in and it should be ready to register again.
This is a user to user help forum. It is not an AT&T support site. I am not an AT&T employee, read the ACE's disclaimer at the bottom of this post