My AT&T Sony Ericsson Z750a is asking for a 4-8 digit "Unlock Code" when I insert a different AT&T SIM then came with the phone. The phone itself is "Unlocked" for other providers, but it seems the SIM is locked to this phone. Sony wants $105 to "reset" the phone. I tried the master reset, but that doesn't work.

Most new Sony will ask for the unlock code when you put a sim in it wont yet accept because it is locked.

Your unlock code is :
CCK: 260704XXXXXXXXXX
NCK: 221877XXXXXXXXXX
NSCK: 40710XXXXXXXXXX
SPCK: 34120XXXXXXXXXX

The letters CCK, NCK, NSCK, SPCK indicate which code to use the different locks on your handset.

So you need to find out which lock is active on the handset ( But usually you'll only need the one marked NCK).

To do this you need to look in a secret menu on the phone

Tap the following in as if you were dialing a number to make phone a call...

*#*#7378423#*#*
A new hidden menu will appear.
Tap on service info
Tap on SIM lock

If you have [x] Network 5 - this means your phone needs the net NCK Code
If you have [x] Service provider 5 - this means your phone needs the SPCK Code

Other Models: 97% Sony Ericsson

1 - Switch ON your phone without SIM Card,
2 - Press 1 time the left arrow,
3 - Press 2 times the button * ,
4 - Press 1 time the left arrow,
5 - The message 'Personalize with MNC2' will appear,
6 - You can now enter the Unlock Code we send to you.

If your phone have a 'JogDial' (ex : Sony Ericsson K700i) you must press 'Down Arrow' instead of 'Left Arrow' for step 2 & 3. We mean by 'Down Arrow' to direct the JogDial down !

W950 models need to use * up * down ** down (up/down using the jog dial on the side).

Satio

Enter # p w + CODE + 1 # into your phone.
Tap repeatedly the star key to get p w + symbols
Older Models

1. Insert a Non accepted SIM card ( EG your new SIM)
2. Switch the phone on
3. Press Left * * Left ( Left is move JogDial stick left )
4. This will open a hidden menu with 4 options (See image)
5. Select 'Network' ( You should see a locked padlock next to the option )
6. Enter the unlocking code we sent you. ( The one marked NCK )

probably because there is a sim lock on the phone preventing u from adding a new sim, if this is the default then u could go to the sim lock area of the phone, & change this by entering the code, if its the first time the default code is either 0000 or 1234, if u bought the phone off someone else u can contact them for the phone, or do a factory reset on the phone & start from scratch, also if the sim is not brand new then it could be protected with a code, or it may not of been activated by the date & has now run out.

Hi if your sony ericsson xperia neo v mobile is asking for sim network unlock pin code once you insert your sim in it then it mean your phone is locked to some other network provider due to this it wont accept other network sim until you unlock it .You can purchase code from sites like SuperUnlockCodes.com they are rendering network unlock code for all mobile models at reliable cost ..You first check that whether the code is available for your country and network provider .If yes then pay for it and unlock your phone .

The phone will ask for "Sim network unlock pin" when you try other network Sim card on a carrier locked phone. To unlock the carrier lock of Sony Ericsson Xperia X10 you can use unlock code. You can get the unlock code from MobileUnlockSolutions.com . There you have to give your Country and current network name along with your IMEI number to get the unlock code. Enter the unlock code when the phone asks for "Sim network unlock pin" to unlock it.

If the phone asks for the pin code then you need to enter the 4 digit password of the phone to unlock.

To unlock :
Default 6 Digit Security code: 123456 or 000000
Default phones codes is 12345 or 00000
Default 4 Digit user code: 1234 or 0000

IT MEANS YOUR PHONE IS LOCKED . IF YOU WANT TO UNLOCK YOUR SONY ERICSON PHONE OR WANT YOUR SIM NETWORK CODE. VIST HERE THIS SITE AND GET YOUR SONY ERICSON SIM UNLOCK CODE. I HOPE THIS WILL HELP YOU.

Contact the carrier that the phone was purchased from. They will need the IMEI to provide you with the correct unlock code.

Try Unlock code from Online site and Unlock it.

call your service company (i.e. sprint tmobile, altell.) they can provide you with a code or they might be able to get you a whole new phone... tmobile has done both for me….
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