Apple Macintosh External Floppy disk drive connector

#Computer#Storage Connectors#Apple

This connector is present on the Macintosh Duo MiniDock and PowerBook Duo Floppy adapter. An HDI-20 1.4 MB drive can be connected to this port.

20 pin Apple HDI-20 connector pin-out & layout

20 pin Apple HDI-20 connector  at the Apple computer, looking into cable-side connector

PinNameDescription
1GNDSignal Ground
2GNDSignal Ground
3GNDSignal Ground
4GNDSignal Ground
5NCNo connection
6+5V+5 volts DC
7+5V+5 volts DC
8+5V+5 volts DC
9+5V+5 volts DC
10NCNo connection
11PH0Phase 0: state control line
12PH1Phase 1: state control line
13PH2Phase 2: state control line
14PH3Phase 3: register write strobe
15WREQWrite request
16HDSELHead select
17ENBL2External drive select
18RDRead data
19WRWrite data
20NCNo connection

Apple Macintosh External Drive connector

Apple SCSI connector