Handset on base not working

It acts as if it's not receiving call identifier. Check with a different handset you know works. Contact provider if the second handset fails to present CID/CLI.

Otherwise you may need to factory reset and reprogram unit.

It is not receiving phone calls or the intercom to the handset does not work? Try reregistering the handset. You must be at the base to do this.

The secret decoder key sequence, provided by AT&T tech support, to factory reset this handset is:

(right softkey "-") * 3 3 1 7 3 4 # (left softkey "-")

The handset they should beep and go into registration mode.

there must be problem with the loud speaker or ringing speaker of the phone.take it to product care center

If your base is a VT2651:
1) take phone off of the base's cradle.
2) enter **335782 on the keypad
3) phone beeps
4) remove all batteries from handsets.
5) reinstall battery in 1st handset, and enter the code number for the base unit (sticker on bottom of base). First handset will be set to phone 1
6) repeat step 5 for all other handsets.

If your base is a VT2656, there is no keypad on the base. I don't know the trick to reregister the handsets. I wish I did, since that is the problem I am having.

Registration:
a. Press MENU-6 to enter the registration mode
b. Press and hold the base’s Registration (REG)
button for 2 seconds until 4 LEDs light up. (Located on the base where you plug in the phone jack)
c. Press handset key “1”, this completes the
registration process. When you register the
handset to BASE 10, the base will assign a
handset ID between 11 and 19. The assigned ID
will be displayed on the handset LCD, indicating
successful registration.
d. Repeat above steps for all additional handsets.
e. The first two handsets registered will be given ID
11 and 12, which gives them administrator
privileges.

YOU might need to deregister the hand set first by holding down the red end (hang up key) and keep it down while holding the # key. If deregister wont work use base unavailable and yes, you are sure twice.

List the handset numbers of those working handsets
Using a WORKING handset follow these directions
Resetting Handsets
If you want to register the handset to a different base or
replace a handset with another one, you must first clear the
registration information from the base and the handset.
1. Press and hold [ ] and [#] for
at least 5 seconds, until the
SYSTEM RESET menu
appears.
2. Select the DEREGISTER HS
submenu. WHICH HANDSET?
appears in the display.
3. Move the cursor to select the handset ID to be de-registered
from the list, and then press the OK soft key. DEREGISTER HS
appears. CHOSE A NUMBER THAT IS NOT ONE OF YOUR WORKING HANDSETS
4. Move the cursor to select YES, and then press the OK soft key.
When ARE YOU SURE? appears, select YES. You will hear a
confirmation tone.
PUT THE HANDSET IN THE BASE CHARGER AND IT SHOULD REGISTER

Hope This Helps - It worked for me

You can unregister your phone without being in the cradle, but to re-register them, just put them back in the cradle.  After being unregistered, they will automatically re-register once they are put back in the cradle of the main base.  Try setting them back in the base cradle to re-register, and hopefully that will work for you.

You might try unplugging the base AND removing the batteries from the handset for 30 minutes. Then reinsert the batteries, place the handset in the cradle in the base, and then plug the base back in. This might allow the handset and the base to re-sync with each other.