Edit Mask Key:

    L - This position cannot be edited.
        (Use Literal mask value).

    a - a-z and A-Z can be entered. 

    A - Characters A-Z  (a-z will be converted to A-Z)

    c - Characters a-z, A-Z, and 0-9

    C - Characters A-Z and 0-9 ( a-z will be converted to A-Z)

    N – Number only 0-9.

    x - All printable characters can be entered.

    X - All printable characters ( a-z will be converted to A-Z).