Epson Apex User Manual page 96

The number of parallel ports you have is
A-6
If you install two option cards with parallel ports,
you must designate one as the primary port and
the other as the secondary port. In this case, you
need to set switches 9 and 10 ON in order to
disable the built-in port.
information that MS-DOS uses also. If MS-DOS
searches the system for a parallel port and finds
only one, it names it LPT1:. If it finds two parallel
ports, it names the primary port LPT1: and the
secondary port LPT2:.
Setting the DIP Switches