his occurs when SIM PIN is entered incorrectly 3 times. Be Careful, do not attempt to guess this code! A PUK code is a security feature enabled when you incorrectly enter your personal PIN code into the phone. PUK stands for Pin Unlock Key and is kept by M2M One to help protect your SIM card from unauthorised use. To get the PUK code, contact M2M One support.
Incorrectly entering the PUK code ten times will destroy your SIM card. This is a safety feature to help guard against an unauthorised person using your SIM card.
Mobile equipment is waiting for PUK code:
AT+CPIN? +CPIN: SIM PUK OK
Unlock the mobile equipment with 8 digit PUK code and new SIM pin: