Connecting External SCSI Devices
Your computer has a port for connecting devices that use the Small Computer System
Interface (SCSI, pronounced “skuh-zee”). SCSI is a standard method for connecting disk and
cartridge drives, CD-ROM drives, scanners, and other devices. The SCSI port permits high-
speed communication between the computer and the device.
The SCSI icon appears above the port on the computer’s back panel.
Note: An authorized Apple dealer or service provider can also install SCSI devices inside
your computer. For more information about the internal SCSI expansion options, see
Chapter 3 and the Technical Information booklet that came with your computer.
The SCSI interface supports up to seven internal and external SCSI devices.
You can connect external SCSI devices to the SCSI port in a chain. The first device in the
chain plugs into the SCSI port; the second device plugs into the first device, and so on.
Before You Connect a SCSI Device
Before you connect a SCSI device to your Macintosh, follow the instructions in this section.
Important This section contains general instructions for attaching SCSI devices to your
computer. Also follow the specific instructions that came with your external hard disk drive
or other SCSI device when connecting the device to your Macintosh. The specific
instructions that came with the device tell how to change a device’s ID number and attach a
SCSI cable or terminator to it.
Make Sure Each Device Has a Unique ID Number
Each external SCSI device connected to your computer must have its own unique ID number
from 0 to 6. The SCSI ID number helps the computer keep track of the devices when several
devices in the SCSI chain are communicating with the computer simultaneously.
The SCSI devices can be in any physical order in the chain; it is not necessary to arrange
them in numerical order.
SCSI port (DB-25)
SCSI icon
32 Chapter 2