Asus AP7500 Hardware Reference Guide - Page 28

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 shielding like that of high speed (e.g. category 5) LAN cabling. II. Components Ultra2 SCSI Drive Red stripe of signal cable Red stripe of power cable Ultra2 SCSI hard disk drive connections IMPORTANT: You must use Ultra2 SCSI ribbon cables for Ultra2 devices. Ultra2 ribbon cables (may be colored red and white) are similar to wideSCSI ribbon cables (normally colored gray) but each pair of wire is twisted to reduce signal interference. 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. Currently 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. 28 AP7500 Hardware Reference Guide