Exabyte EXB-8205 manual Scsi Cable, General Requirements

Appendix A Installation Requirements

This appendix lists the requirements for the following items: SCSI cable

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SCSI connector Power cable Power connector

It also provides guidelines for attaching the tape drive to a frame and adding optional chassis grounding.

SCSI Cable

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

132ohms (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.

Note: To minimize discontinuities and signal reflections, ensure that cables used on the same bus have the same impedances.

36 EXB-8205 and EXB-8505 (Standard and XL) 302967