A PUK code is required if a GSM SIM card was locked after entering the wrong PIN code three times in a row. Entering a wrong PUK code ten times in a row disables the SIM card permanently.

In GSM mobile phones, the PIN is normally associated with the SIM card (not the phone ... handset is locked until you enter another code, called a PUK code. Both the PIN and the PUK codes are ...