IBM RT PC Options Installation page 99

General Instructions
The following pages supply general instructions for handling adapters. Read
these instructions now, but do not unpack any adapters until you read the
instructions for installing each one.
Before doing any procedure, ensure that you turn off the power to the
system unit and that you unplug the power cable from the electrical outlet.
When you are finished, see "Installing the Covers on the System Units" on
page 3-15.
3-4 Options Installation