ICP GDT RS Series, User Manual

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Avoid using SCSI cables with more connectors than actually needed. Never select a SCSI
mode or operate a SCSI device with a cable that is not appropriate for this mode.
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The minimum distance between two connectors of a SCSI cable is 20 cm.
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Avoid cable stubs. If this is not possible, keep the stub length below 10 cm.
“Star cabling” are not allowed.
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Keep the number of transitions from flat to round cables and vice versa as small as pos-
sible. It is usually best is to use flat or round cables, only.
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Check these points when routing SCSI cables:
- Avoid kinks in the SCSI cable
- Do not roll the SCSI cable up on itself
- Avoid routing the cable next to other cables
- Avoid routing the cable in the vicinity of noise sources such as power supplies
- Avoid routing the cable over sharp edges and in areas where it could get caught up
- Avoid routing/sticking the cable directly onto metal surfaces
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When using internal Wide/Ultra2 SCSI cables make sure that the cable has in both
modes, SE and LVD, the correct impedance. The "Spectra Strip" cable material from
Amphenol fulfills the required specification (color coding: first pair blue/white all other
pairs orange/white) and complies with the ANSI T10/1142 D document. ICP vortex offers
a finished cable assembly which is based on this raw material (Order No.: 8839). The
cable has twisted cable pairs.
For external Wide/Ultra2 SCSI round cables the same rules and specifications apply. ICP
vortex offers here two cables: Order No.: 8844 for the 3 meters round cable and Order
No.: 8877 for the 1 meter round cable).
When making home-made SCSI cables, make sure that the insulation displacement connec-
tors are properly aligned and firmly pressed into the flat ribbon cable. Otherwise, the whole
cable might turn out to be a big short-circuit. Furthermore, check carefully that PIN 1 of the
cable connects to PIN 1 of the connectors. A simple short-circuit and continuity test before
running the devices helps you to save time and money.
The same warnings as for home-made cables apply when you buy non-brand cables. If you
plan to run Fast-20 (Ultra) or Fast-40/80 (Ultra2 or Ultra 160) devices, you should explicitly
ask your dealer if these cables are appropriate for the desired mode. (Note: The ICP product
range also includes some high quality SCSI accessories. Please see section B.4.4 of this
User's Manual or check our Website: http://www.icp-vortex.com, for further details).