Model: Samsung SGH-T459 (Gravity), Pixon, P180, F700, S7330, Z300...:

1. Power on without SIM
2. From the standby screen, use the dial pad to enter the number sequence
3. Type in #7465625*638*Unlock code# (8 digit unlock code*)
4. Device should say: “Network Lock Deactivated”

If you need your unlock code to use your phone with another provider, you can get your unlock code on unlock-phone-samsung.com