A mobile station is disclosed which may be operated in both a set-up programming mode and in an authentication key programming mode. The authentication key programming mode may be invoked through a series of keystrokes on a keypad in the mobile station. The mobile station allows the entry of a separate authentication key for each mobile station identification number stored in memory. The mobile station also checks the accuracy of the entered authentication key and alerts the user as to whether the entered authentication key is valid or invalid.