Computer Personal Computer User's Manual

Connecting external SCSI devices (such as a scanner or external hard disk)
Your computer has a port for connecting devices that use the Small Computer
System Interface (SCSI, pronounced “skuh-zee”). SCSI devices commonly
used with the Macintosh include hard disk drives, CD-ROM drives, scanners,
some printers, and tape or cartridge backup drives. The SCSI port permits
high-speed communication between the computer and the device. The SCSI
icon appears below the port on the computer’s back panel.
You can connect 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. You can attach up to six external SCSI devices to the SCSI
port. All SCSI devices connected to this chain must have their own unique ID
number (no two devices can use the same ID number). If your computer came
with the optional CD-ROM drive installed, this drive is also part of the SCSI
chain and uses SCSI ID number 3. The computer itself (the main logic board)
uses SCSI ID number 7.
IMPORTANT “Before You Connect a Device” and “Connecting a SCSI Device,”
both later in this chapter, contain 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.
SCSI port
SCSI icon
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Expanding Your Computer and Using Special Features