Model : Nec N342i
1 - Switch ON your phone without SIM Card,
2 - Compose : **00012*CODE#.
Model : All others NEC
1 - Switch ON your phone without SIM Card,
2 - Compose : #7320*CODE#.
Model : old NEC
1 - Switch ON your phone without SIM Card,
2 - Compose : #3210*CODE# and press Call Button.