Re: RAMfast to SCSI cable

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <30caa206.3848592@nnrp.crl.com>, Dan Brown <danb@a.crl.com> wrote:
> dempson@atlantis.actrix.gen.nz (David Empson) wrote:
> 
> > to minimise noise being picked up or radiated.  You should definitely
> > not use a ribbon cable.
> 
> 	According to Harold Hislop and Doug Pendleton on GEnie, both
> of whom seem _very_ knowledgable in SCSI-related issues, ribbon cable
> is exactly what's specified in the original ANSI specs.  However, this
> refers only to 50-50 cables; wiring a 25-50 using IDC connectors would
> be hideous.

With a 50-to-50 ribbon cable, shielding is less important, because
every second wire is a ground signal.

This is not the case with a 25-to-50 "system" cable.


I haven't read the part of the SCSI standard on cable specifications,
but I would expect that ribbon cables are only supposed to be used for
short distances, and only within a shielded enclosure (e.g. a computer
or hard drive case).
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand