Technical information

CHAPTER 3
Devices and Ports
External SCSI Port 33
interoperate with an OHCI controller. Those devices will not be supported by
the Macintosh USB system software.
External SCSI Port 3
The computer has a connector for adding external SCSI devices such as a hard
disk drive or a removable media drive. The connector is an HDI-30 high-density
30-pin connector. The signal assignments are listed in Table 3-2.
The computer can operate in SCSI disk mode (also called target disk mode) as
long as there is a valid system image on the hard disk.
Table 3-2 Signals on the HD-30 SCSI connector.
Pin Signal name Pin Signal name
1 SCSI_LINK_SEL_L(2) 16 SCSI_DB(6)
2 SCSI_DB(0) 17 GND
3 GND 18 SCSI_DB(7)
4 SCSI_DB(1) 19 DBP_L
5 TERMPWR 20 GND
6 SCSI_DB(2) 21 REQ_L
7 SCSI_DB(3) 22 GND
8 GND 23 BSY_L
9 ACK_L 24 GND
10 GND 25 ATN_L
11 SCSI_DB(4) 26 CXD_L
12 GND 27 RST_L
13 GND 28 MSG_L
14 SCSI_DB(5) 29 SEL_L
15 GND 30 IXO_L