Epson 486SX - Manual (Page 30)

Follow these steps to connect a mouse:
1. Make sure the computer is turned off.
2. Hold the mouse connector so it is oriented properly with its
port (marked with a mouse icon). Insert the connector as
shown below.
interchangeably. Be sure to plug the mouse only into the
3. After you connect a mouse, you may need to add
commands to your MS-DOS CONFIG.SYS file to enable
your computer to use it. See your MS-DOS and mouse
manuals for instructions.
1-12 Setting Up Your System