Epson ActionNote - Manual (Page 82)

Note
If you are using an external
diskette drive, use the 6-pin port
on the
back of its connector cable to connect a PS/2 device.
Connecting an External Keyboard or Keypad
If you are typing text or entering numbers for extended periods
of time, you may want to connect an optional external
keyboard or keypad. You connect either of
these
devices
directly to the EXT KB port on the computer, as shown below.
5-8 Connecting Optional Devices