I had an AT&T CL84109 corded/ cordless phone with 4 handsets. the base unit was damaged in an electical storm. I purchased another 84109. How can I deregister the handsets without the original base so I can use them with my new phone?

SOURCE: Cordless Handsets don't work

in manual it states that you need to give permission on corded base for handset to link to cordless phone.

SOURCE: DeRegistering a Damaged Cordless Phone????!!!!

If you are still looking for an answer on dereg of a handset, the manual says Menu - 0-0-2 then 3-3-5-OK then select the handset you want to cancel/deregister

SOURCE: unable to register handsets to

From the manual:

1) Before registering the extra handset, the battery pack MUST be charged for 15-20
hours.
2) With the main base in standby mode, press the MENU soft key on the base.
3) Press /vol/∧ or /vol/∨ on the base to select H S R e g i s t r a t i o n, and then
press the OK soft key.
4) On the handset, press and hold # for two seconds. To cancel registration, press
the CANCEL soft key on the base.
5) While the handset is registering, H a n d s e t R e g i s t e r i n g will appear in the Handset
LCD. When R e g i s t r a t i o n C o m p l e t e is displayed, the handset has been registered
to the base. If R e g i s t r a t i o n F a i l e d appears, please try these steps again.


Geno

SOURCE: AT&T Model # 1487 Phone

http://telephones.att.com/telephones_ui/support/support_index.cfm

Go to the above web site. It helped me.

SOURCE: cordless phone does not connect

You may need to reset the Telephone Answering System. Complete the following steps to reset the Telephone Answering System:
Step 1: Disconnect the power to the telephone base.

Step 2: Wait a few minutes and then reconnect the power to the telephone base and charger.

Step 3: Set the day and time.