Epson 20 - Manual (Page 22)

4. Connect the other end of the cable to the printer as shown
below. To secure the cable, squeeze the clips at each side of the
printer port and push them into place.
5. Plug the printer’s power cord into an electrical outlet.
Using the Serial Interface
If you have a printer, modem, mouse, or any other peripheral with a
serial interface, you can connect it to the serial (RS-232C) port on the
back of the computer.
\
serial port
1-8 Setting
Up
Your System