For the safety of wireless subscriber’s data and monetary investment, many GSM phone manufacturers (such as AT&T and T-Mobile) provide an option to place a PIN lock on a SIM card. This PIN lock keeps strangers from accessing what’s on the SIM card or making calls with the locked phone. If you enter an incorrect PIN code three times, a PUK (Pin Unlock Key) code will be requested. This number is provided by the service provider. Writer Bio
