Asus PCI-SIU2 User Manual page 20

4b Installation of external SCSI devices
Use the 68-pin external Ultra2 SCSI connector to connect your exter-
nal Ultra2 peripherals. Ultra2 external cables are not included in the
kit. Installation of external SCSI cables can be performed after the
cover has been closed. The cable is limited in length to a total of 12
meters including any internal cabling. The external cable can be daisy
chained to include up to 15 devices with the host adapter in combina-
tion with internal devices. The external cable is designed to be in-
serted only one way, requiring termination at the end peripheral de-
vice (FIGURE 9).
NOTE:
We recommend keeping your Ultra2 peripherals seperate from your
non-Ultra2 peripherals. Connecting a non-Ultra2 peripheral to the
Ultra2 SCSI connector forces the Ultra2 SCSI segment and any at-
tached peripherals to drop down to UltraSCSI performance levels (40
MBytes/sec).
To increase the reliability of the cabling being used with the host adapter, it is
recommended that the following guidelines be observed:
• SCSI-1 – Cabling up to 6 meters (20 feet)
• UltraSCSI – Four devices, up to 3 meters (10 feet)
• UltraSCSI – Eight devices, up to 1.5 meters (5 feet)
• Ultra2 (point-to-point configuration) – Up to 25 meters (82 feet)
• Ultra2 (multiple interconnect config) – Up to 12 meters (39 feet)
• Impedance of the cable should be 120 (±8 ohms); Ultra2
• Impedance of the cable should be 90 (±8 ohms); UltraSCSI & FastSCSI.
• Use high quality shielded connectors for external devices.
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3. Hardware Installation
FIGURE 9 | External cable connection
ASUS PCI-SIU2 User's Manual