Dale, look in the Installation Guide at the beginning of Chapter 5,
"Digitizer Options". It only describes ports A & B, and the differences in
pin configuration between them (special cabling may need to be done if you're
having problems here).
Apparently only two ports (A & B) are supported, even though your machine has
four. I don't know of a way to "patch" this. I guess if it says to enter A or
B, that means to enter A or B (not a hex address)! When you enter A or B,
does it work? Or are you trying to use one of the other ports? Perhaps an
inexpensive switch box may be the ticket. =SM=