American Megatrends MAN-758 - Manual (Page 43)

Chapter 1 Hardware Installation 39
Step 11 Connect SCSI I/O, Continued
SCSI Termination The SCSI channels on the MegaRUM 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 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.