On Tue, 11 Jan 2000, James Manning wrote:
> > > If you cut the cable
> > > lengthwise (no, don't cut the wires) between wires (etc.)
> >
> > I don't know about IDE, but I'm pretty sure that's a big no-no for SCSI
> > cables. The alternating conductors in the ribbon cable are sig, gnd, sig,
> > gnd, sig, etc. And it's electrically important (for proper impedance and
> > noise and cross-talk rejection) that they stay that way.
> >
> > I think the same is probably true for the schmancy UDMA66 cables too...
>
> So just check with a cable spec and make sure you're not separating a
> data signal from its ground return path. Throw some mag rings around
> the thing if you want, but since we're (hopefully) terminated properly
> (no reflection) the crosstalk issues aren't huge... they suffer more
> through the LC matrix of connector adaptors than this split would cause :)
,,Termination`` means nothing else then a resistance at the end of the
cable (each pair) that is equivalent to the cable impedance. And the
impedance depends on the cable geometry (and material, of course).
So IMHO you can't divide the flat cable to the pairs (unless they're
twisted pairs) or even single wires without an impedance change
of the cable section involved.
BoChal.
