Hello I have a model : 27957 GE1-A It says

Unfortunately, the old handsets may not be compatible with the new base. The DS6251-2 base only communicates with the DS6250 accessory handset. See the accessory list here: https://www.vtechphones.com/store/pd/4158/DS6251-2-2-Line-2-Handset-Cordless-Phone-with-Answering-System-Smart-Call-Blocker . If the old handsets have been deregistered from the previous base unit, place a handset in the cradle on the base. Wait to see if the handset is registered. Alternately, press and hold Page until you see Registering. Release the Page button. Then press Quiet/# (below 9) on the handset. Wait for the handset to be registered.

To deregister handsets from the DS6251 base, press and hold Page. You'll see Registering Please Wait followed by Deregister all devices? At this point, release the Page button. Then press and release Page or the soft key for Yes.

I hope this helps. These are shown in the manual for the accessory handset. The manual is on available on the accessory handset page: https://www.vtechphones.com/store/pd/4184/DS6250-2-Line-Accessory-Handset-for-DS6251-series-phones . The current link to the manual is https://cdn-web.vtp-media.com/products/DS/DS6250/DS6250_CIB_V2_20200623.pdf .

Cindy Wells

Welcome to FixYa.

1. Turn OFF your handset (TWX977) and any other handset registered to the base (9466).
2. Unplug the base from its power source.
3. Unplug the phone line from the base.
4. Wait for 15 mins.
5. Plug back the power source and the phone line.
6. Turn ON the handset (TWX977)
7. Reset the handset (TW977) by doing the following:

• Press the MENU soft key. Select the DEREGISTRATION submenu.
• ARE YOU SURE? appears. Move the cursor to select YES. Press the OK soft key.
• To clear other handset information, please follow these steps:
• From the handset, press and hold [ ] and [#] for more than 5 seconds. Select the DEREGISTER HS submenu.
• 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. Move the cursor to select YES. Press the OK soft key.
• ARE YOU SURE? appears. Move the cursor to select YES, and then press the OK soft key. You will hear a confirmation tone.

8. Register the handset by doing the following:

• With the base in standby, press the MENU soft key.
• Move the cursor to select REGISTER HANDSET. Press the OK soft key.
• On the handset, press and hold [#] until you hear a beep.
• While the handset is registering, HANDSET REGISTERING will appear in the LCD. When REGISTRATION
• COMPLETE is displayed; the handset has been registered to the base. If REGISTRATION FAILED appears,
• please try these steps again.

Thank you for using FixYa.
Have a great day.
Jas247

To register a handset to your telephone base
Make sure the handset battery is installed and charged properly. You have to enter a 15-digit telephone base ID to register the handset to the telephone base.

To find the telephone base ID and register the handset:

1. On the telephone base, press the MENU softkey when in idle mode to enter the feature menu. Press the or softkey to scroll to the DISPLAY BASE-ID menu, then press the OK softkey. The telephone base ID will be displayed.

2. On the handset, use the keypad buttons to enter the telephone base ID and press the OK softkey.
Press the softkey to move the cursor.

3. The handset will first display PLEASE WAIT!!, then T23 PD followed by SEARCHING FOR BASE. The screen will finally display HANDSET X when the registration is successful.
NOTES:

1. If the registration is not successful, the display will show NO BASE SUBSCRIPTION. Try the registration process again.

2. If an incorrect base ID is entered, the base ID will disappear and ENTER BASE ID will be displayed.

In case of a problem or clarification or my solution was insufficient, don't hesitate to post me a reply.

If you are satisfied, rate my solution with the "thumbs" or (even better) add a testimonial.

Up to 6 handsets can be registered with the DECT 1480 phones. I have the 5 phone unit and needed to add the 6th phone. All I got was "Searching" in the display and the battery wouldn't even charge!

So here's what you have to do to get additional phones (up to 6 units) to work with the base. If you can get past step 1, it's a snap...

Step 1: Place a charged battery in the handset. This could be a problem if all your handsets are not registered, since unregistered phones don't charge (who thought of that design?). What I did was SWAP the battery from an already registered and charged phone with the new unregistered phone.

Step 2: Here's where the magic happens. Press the 'END' and '#' keys simultaneously... hold them down until a System Reset menu appears. Select "Deregister HS" and press Menu.

Step 3: Now, do the same thing again (hold down END and #), but this time select Base Unavailable and press Menu. You will see Base Unavailable Yes/No... Select Yes. Then place the handset in the base, wait a few seconds, and Voila!. it's registered. You can even change handset numbers using this menu if you play around with it.

Thank you, helpful employee at Costco for supplying the magic code. And hey there, UNIDEN... including this in the operation manual would have saved many customers much grief with de-registered phones!

Enjoy!

Since you neglected to specify the model of your Uniden DECT 6.0 system I can only suggest you select it from the list beginning here to download a copy of the manual.

Your handset model : SGH-E90.
You should have a notification from provider after send text message SUPERSURF50

To be able to register your replacement handset, you must de-register all the handsets from the VT2656 base unit.

Follow the steps below to de-register your handset(s) from the VT2656 base:

1. Take out the handset that sits on the base.
2. Unplug power from the base.
3. Hold down PAGE while reconnecting power. When the In Use light blinks, release the PAGE key.
4. Hold down PAGE key for 5 seconds. When the In Use light begins to flash, release the PAGE key.
5. The handset charging light will blink 5 times. Within 5 seconds from when it stops blinking, press PAGE once.

You must register the handset(s) by following the steps below:

1. After charging the handset, remove it from the cradle, the LCD display will read "SEARCHING FOR BASE".
2. Press "NEW" and then enter the 15-digit Base ID code, located on the underside of the VT2656 base unit.
3. Press "OK". The handset will display "PLEASE WAIT!!".
4. Wait approximately 15 seconds. The handset will display "FOUND BASE". If the handset displays "BASE BUSY TRY LATER", this indicates that the system is in use. Wait until the base unit is in the idle (on hook) mode and repeat steps 2-4.

Registering a unit Operating additional
handsets
Additional handsets
Up to 6 handsets can be registered to
the base unit.
Important:
L See page 6 for information on the
available model.
Registering a handset to a
base unit
The supplied handset and base unit are
pre-registered. If for some reason the
handset is not registered to the base
unit, register the handset.
1
Handset:
{MENU} i {#}{1}{3}{0}
2
Base unit:
Press and hold {LOCATOR} for 4
seconds until the registration tone
sounds.
L If all registered handsets start
ringing, press the same button to
stop. Then repeat this step.
L The next step should be
completed within 90 seconds.
3
Handset:
Press {OK}, then wait until a long
beep sounds.
4
{OFF}
Note:
L While registering, "Base
registering" is displayed on all
registered handsets.
L When you purchase an additional
handset, refer to the additional
handset's installation manual for
registration.

This works on MY panasonic; May work on yours too!

Registering a handset
The included handset and base unit are
preregistered. If for some reason the
handset is not registered to the base
unit, register the handset.
1 Handset:
{MENU} i {0}{0}{1}
2 Base unit:
Press and hold {LOCATOR/
INTERCOM} until the IN USE
indicator flashes.
LAfter the IN USE indicator starts
flashing, the rest of the procedure
must be completed within 1
minute.
3 Handset:
Press {OK}, then wait until a beep
sounds.
4 {OFF}
Registering an additional handset
See page 5 for information on the
available model.
Start from step 2.

I reviewed the user guide for that model, and I only see that it is an answering machine. I may indeed be wrong, but is there a chance you have a different model unit? Regardless of the model, normally you have to put the base in registration mode simultaneously when the handset it put in registration mode like you were doing before. If you do not have the user guide you can join Beoworld.org for $27 a year and download it for "free". I am curious to know if you have a different model or if you can register cordless handsets to the 1200. Maybe you can post an update. Just learning this model myself. Good Luck