Apple PowerBook (Duo 270C) - Manual (Page 267)

Using the PowerBook Duo Floppy Adapter
The Duo Floppy Adapter is an optional device that allows you to
connect a Macintosh HDI-20 External 1.4 MB Floppy Disk Drive
and up to three Apple Desktop Bus (ADB) devices—such as a
keyboard or mouse—to your computer.
Connecting the floppy adapter, disk drive,
and input device(s) to the PowerBook Duo
1. Make sure the PowerBook Duo is in sleep or shut
down. (Choose Sleep or Shut Down from the Special
menu.)
If you try to connect the floppy adapter with the computer
turned on, the computer turns itself off. You will lose any
information you did not save.
continues .
Chapter 13: Building a PowerBook Duo System 251