User`s guide

Chapter 1 Hardware Installation

Step 10 Connect SCSI I/O, Continued

SCSI Termination The SCSI channels on the MegaRUM II motherboard

use active termination for each SCSI channel. You must

terminate the SCSI bus properly. The SCSI bus on each

SCSI channel is an electrical transmission line and it must

be terminated properly at both ends to minimize

reflections and losses. You complete the SCSI bus by

setting termination at both ends.

Do not add terminators in the middle of the SCSI bus. The

end devices must be located as close as possible to the

terminators. A simple rule is to place SCSI terminator

after the last SCSI device on each of the SCSI connectors.

MegaRUM II automatically terminates the onboard SCSI

connectors.

Stub length The stub length shall not exceed 0.1 meter. The spacing of

devices on the SCSI bus should be at least three times the

stub length to avoid stub clustering.

SCSI Cables Teflon flat ribbon cables give the best performance in the

Ultra-SCSI environment. These cables should be used for

all internal cabling. To minimize discontinuities and

signal reflections, the use of cables with different

impedance’s on the same bus should be minimized.

Cont’d