Here is how you can get into the admin settings on your Samsung Blackjack… this is really handy as the Network and Call settings menu enables you to force it off 3G if you should so choose.. (saves battery life if you’re not on 3G)

You can get into the admin settings etc with the following code:
*#1546792*#
Menu:
1 Version
2 Preconfiguration
3 Network and Call settings
4 Internal

Two of the menus require a password, it is *#81230*#