Wanted: DEC cables BC08J

From: vrs <vrs_at_msn.com>
Date: Wed Oct 20 08:44:45 2004

From: "Paul Koning" <pkoning_at_equallogic.com>
> Ethan> Sorry... never even _seen_ those. You could probably make a
> Ethan> set from a prototyping card and some ribbon cable, though.
> That may not work... you want controlled impedance cable. I looked
> for the spec, but didn't see it; it may be the same as Unibus cable,
> which is documented in the Unibus handbook.
> Conventional ribbon cable is not controlled impedance, though there
> exists higher end cable that is.

It is pretty easy to find ribbon that is spec'd for impedance. It would say
it is more a matter of avoiding the low-end ribbon, these days.

The older Negibus/Posibus cables are spec'd for 93 ohm coax. I suspect
you'd do OK with 100 ohm ribbon.

I think a tougher issue with ribbon is how to keep the cables from sitting
on top of each other and having a mess of crosstalk. The older coax doesn't
have that problem :-). I am also building a few Negibus/Posibus cables out
of CAT5e, in an attempt to mitigate that problem.

Received on Wed Oct 20 2004 - 08:44:45 BST

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