Epson 20 - Manual (Page 148)

To add a device to the list, press 1 and then Enter. The program
displays a list of other devices that are not currently included in the
DEVICE LIST You see a menu similar to this:
Additional DEVICE LIST
4 - Monochrome display adapter and CRT
7 - Math coprocessor
12 - Alternate serial port
21 - Alternate parallel port
81 - Parallel port (on video adapter)
0 - Exit
Enter the number of the item to add:
Type the number of the item you wish to add and press Enter. You
can add as many devices as necessary. When the DEVICE LIST is
complete, press 8 followed by Enter.
To remove a device from the list, press 2 and Enter. The screen
displays the current DEVICE LIST and the prompt:
Enter the number of the item to delete:
Type the number of the item you wish to delete and press Enter. You
can delete as many devices as necessary.
C-4 Performing System Diagnostics