Asus Dual Pentium II Department Server AP2500 User Manual download pdf (Page 32)

32 AP2500 Hardware Reference Guide

II. Components

II. System Components

Ultra2 SCSI Disk Drive

The Ultra2 SCSI disk drive has separate signal and power connections. The

power connector is the same as standard hard disk drive power. The signal

cable is different. For proper signal stability in Ultra2 speeds, a special twisted

ribbon cable must be used. Each pair of wires are twisted for signal shield-

ing like that of high speed (e.g. category 5) LAN cabling.

IMPORTANT: You must use Ultra2 SCSI ribbon cables for Ultra2 devices.

Ultra2 ribbon cables (may be colored red and white) are similar to wide-

SCSI ribbon cables (normally colored gray) but each pair of wire is twisted

to reduce signal interference.

Ultra2 SCSI hard disk drive connections

Red stripe of signal cable

Red stripe of power cable

External Ultra2 SCSI Terminator

To prevent SCSI signal loss, the provided external SCSI terminator must be

used at the end of the 68-pin SCSI cable. 50-pin SCSI cables may also use

terminators but usually use termination jumpers on the device itself. Cur-

rently Wide-SCSI devices have termination jumpers but Ultra2 devices do

not. Some manufacturers ship SCSI devices with the terminator set, others

do not. All termination jumpers must be removed along the cable where the

external SCSI terminator is used.

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Asus Dual Pentium II Department Server AP2500 User Manual Page 32