Samsung SGH-D606 - Manual (Page 150)

Access Codes
144
If you enter an incorrect PIN2 three times in succession, the code is
disabled and you cannot access the functions until you re-enable it
by entering the PUK2.
To change the PIN2, see page 141 (Menu 9.7.8).
PUK2
The 8-digit PUK2 (PIN Unblocking Key 2), supplied with some SIM
cards, is required to change a disabled PIN2. If you lose the code,
contact your service provider.
To re-enable your PIN2:
1. Enter the PUK2 and press the OK soft key.
2. Enter a new PIN2 of your choice and press the OK soft key.
3. When the Confirm New PIN2 message displays, enter the same
code again and press the OK soft key.
If you enter an incorrect PUK2 ten times in succession, you will not
be able to access the functions requiring the PIN2. Contact your
service provider for a new card.