Samsung smartphones that are purchased from a carrier are generally locked to the carrier’s SIM card. This means, if you purchase the smartphone from AT&T, you have to use an AT&T SIM card together with the smartphone. The smartphone will not work with SIM cards from other carriers.
If you need to use your locked Samsung Galaxy Note 2 or Samsung Galaxy S3 with another carrier apart from the one you bought it from, here is a way to unlock your Android easily and free of charge. Unlocking will enable you to use the Samsung Galaxy S3 and Samsung Galaxy Note 2 with a SIM card from other local carriers as well as carriers abroad. First of all, you need to prepare a SIM card from a different carrier than you are currently using.
Then follow these steps to unlock;
1. Insert the new SIM card on your Galaxy Note 2 or Galaxy S3.
2. Switch your device off and then back on again.
3. Go to the dialpad on your phone and type in *#197328640#.
4. Then choose [1] UMTS > [1] Debug Screen > [8] Phone Control > [6] Network Lock > Options [3] Perso SHA256 OFF.
5. Wait for around 30 seconds before going back into your main menu by selecting back.
6. On the main menu, you should see “Network Lock” now choose [4] NW Lock NV Data INITIALLIZ.
So your Samsung Galaxy S3 or Samsung Galaxy Note 2 is now unlocked. You can use it with any carrier you want or even send it to family or friends overseas. This code had been used by Samsung for a while now so it should work on some older Samsung devices. As for devices like the Samsung Galaxy S4 and Note 3, it isn’t possible using this method.
