How to Enter Unlock Codes on C3, C3B, C120, C530 (Slate), C610, C630, C810 (Duo), C820 (Matrix Pro):

1) Power on with Non-allowed SIM card
2) Enter unlock code when prompted
3) Enter code using the ON-SCREEN keyboard (This is if the screen HAS an ON-SCREEN keyboard) when unlocking a Pocket PC Phones
4) Press Ok
5) Phone Unlocked

ISSUE PANTECH DUO (C810): Many times you may face an issue saying “This phone only accepts SIMs from specific networks, and has been blocked. Contact your customer service center for the unblock code. Unblock code:
New pin:
Confirm new pin:

If you get this message, the issue is that your phone needs to have the newest Windows Mobile 6.1 installed.

How to Enter Unlock Codes on C150, C520 (Breeze), C740:

1) Put AT&T SIM card in C740
2) Turn on
3) Enter *#865625# on idle screen
4) SIM Unlock Process – Click Yes.
5) Enter 8 digits unlock code and click OK (soft key)
6) Re-enter the unlock code.
7) Unlock Process Complete
8) Click OK (soft key)