Epson LT-286 - Manual (Page 20)

Connecting to the Serial Interface
If you have a printer or other peripheral device that uses a serial
interface, connect it to the serial (RS-232C) interface on the back
of the computer.
The Equity LT-286 uses a 9-pin, D-shaped male connector, so be
sure you have a compatible cable or an adapting cable that converts
the 9-pin output to the standard 25-pin output. To connect a serial
device, follow the steps above for connecting a parallel device.
You need to make sure the serial port is set up so it functions
properly. If you are using the port for a serial printer, you must also
redirect printer output from the parallel port to the serial port. Use
the MS-DOS MODE command (or the Epson MENU program) to
make these changes. See your MS-DOS manual for instructions.
Setting Up Your System 1-7