Exabyte EXB-8500c 8mm manual SCSI Cable Requirements, General Requirements

Appendix A Installation Requirements

This appendix provides specific installation requirements for the tape drive. It also provides guidelines for the following tasks:

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Selecting the correct SCSI cable and connector (pages 37 and 38)

Attaching the tape drive to a frame (page 38) Providing chassis grounding (page 40)

Connecting the tape drive to the power supply (page 40)

If you have already installed the tape drive in a PC, you can skip this appendix.

SCSI Cable Requirements

The SCSI cable for connecting the tape drive to the host is not provided with the tape drive. You must provide a cable that complies with the appropriate safety and regulatory agency requirements. To comply with FCC, Canadian DOC, and VDE limits, the tape drive requires shielded cables when the cables are external to the mounting enclosure.

General Requirements

Use a 50-conductor flat cable or 25-signal twisted pair cable. A minimum conductor size of 28 AWG is recommended to minimize noise effects and ensure proper distribution of terminator power.

Ideally, to match the cable terminators, the cable should have a characteristic impedance of 122 ohms (differential) or 132 ohms (single-ended). However, since cables with this high of a characteristic impedance are not generally available, somewhat lower impedances are acceptable. A characteristic impedance of 100 ohms ± 10% is recommended for unshielded flat or twisted-pair ribbon cable. A characteristic impedance greater than 90 ohms is recommended for shielded cables.

December 1993 EXB-8500/EXB-8500c 39