How to Unlock a Samsung Gravity Phone

1. Obtain the IMEI number for your phone. Do this by typing *#06# on your phone's keypad. Your phone will then display a number. The first 15 digits of the number are your phone's IMEI number. Record them for later use.
2. Contact T-mobile Customer Care at 1-800-866-2453. Tell the representative you would like to unlock your phone's SIM card. Give the representative the IMEI number and he will give you the unlock code. Record it accurately, because inputting an incorrect unlock code may make your phone unusable.
3. Remove your phone's SIM card by taking off the back cover of the phone and removing the battery. Slide the SIM card, located underneath the battery, out of the slot. Replace the battery and back cover.
4. Turn on your phone. The screen will prompt you to insert the SIM card; disregard this message. Enter #7465625*638*UNLOCK_CODE# from your keypad. 'UNLOCK_CODE' should be replaced with the 8-digit code the T-mobile representative gave you previously. The screen will read, 'Network Lock Deactivated' if you successfully unlocked your phone.