# Apple Macintosh External Drive

19 PIN D-SUB CONNECTOR

Pin | Name | Description
--- | --- | ---
1 | Ground |
2 | Ground |
3 | Ground |
4 | Ground |
5 | -12V | -12 VDC
6 | +5V | +5 VDC
7 | +12V | +12 VDC
8 | +12V | +12 VDC
9 | ? | ?
10 | PWM | Regulates speed of the drive
11 | PH0 | Control line to send commands to the drive
12 | PH1 | Control line to send commands to the drive
13 | PH2 | Control line to send commands to the drive
14 | PH3 | Control line to send commands to the drive
15 | WrReq- | Turns on the ability to write data to the drive
16 | HdSel | Control line to send commands to the drive
17 | Enbl2- | Enables the Rd line (else Rd is tri-stated)
18 | Rd | Data actually read from the drive
19 | Wr | Data actually written to the drive

Contributor: Joakim Ögren

Source:
Technote HW19: Pinouts at Apple Technical Notes

Copyright © The Hardware Book Team 1996-2001.
May be copied and redistributed, partially or in whole, as appropriate.
Document last modified: 2000-07-09