LetterXSymbol and NumberNSymbol change the symbol displayed
for the corresponding selection value. There is probably never a need to
use this setting. It could be used, for example, on a jukebox with an
alphanumeric selection scheme where the number is first rather than the
letter. In this case, the symbols would be swapped as follows:
LetterASymbol = 1
LetterBSymbol = 2
LetterCSymbol = 3
LetterDSymbol = 4
Number1Symbol = A
Number2Symbol = B
Number3Symbol = C
Number4Symbol = D
Note that a symbol can contain more than one letter or number.
Default value: Equal to the normal symbol for that value.
SkipLetterX and SkipNumberN skip the specified letter or
number in the selection order. Many jukeboxes did not use the letters
I or O to avoid confusion with 1 and 0. If SkipLetterX
or SkipNumberN are set to True, the specified letter or number
will not be available. If a key is mapped to that letter or number, it
will trigger MSG_INVALID if pressed.
Default value: False