Epson 3865X Plus - Manual (Page 145)

If you install an optional memory card, use the setup program
that comes with the card to configure the computer for use with
the memory card. See your memory card manual for
instructions.
Additionally, you may need to add some commands in your
configuration files. See your MS-DOS Reference Manual and
the manual that comes with your option card for instructions.
You may also want to test a newly-installed option. Some
options come with their own diagnostics test programs, and you
can test others with the diagnostics programs on your Reference
diskette. You can use the System diagnostics program on your
Reference diskette to test the following:
System memory
Math coprocessor
Serial and parallel ports
Disk drives
Monitors and display adapters
Dot-matrix printers.
See Appendix E for instructions.
Installing and Removing Options 5-39