Epson EQUITY 3865X/20 PLUS - Manual (Page 139)

Installing a Math Coprocessor
Your computer has a socket on the main system board to
accommodate an Intel 80387SX (20MHz) math coprocessor.
A math coprocessor speeds up the numeric calculations your
computer performs when using certain application software. It
also increases the speed at which graphic images are displayed
on your monitor when you use graphics-oriented software.
It is best to have your dealer install a math coprocessor for you;
it is a delicate component that can be damaged easily if it is
installed incorrectly.
If you install it yourself, be sure to read the manual that came
with your math coprocessor, if you received one. Then follow
the steps in this section to install it in your computer. However,
be sure to read all of the warnings and instructions carefully so
you do not injure yourself or damage the coprocessor or your
computer.
Caution
To avoid generating static electricity and damaging your
math coprocessor, remain stationary as you install it.
Installing
and Removing Options 6-19