> Hi Gang,
> Not to be argumentative, but, what about interference?  In audio systems,
> great care is often taken to ensure the complete separation of cables so
> as to not pick up any interference from other cabling, such as keeping
> the speaker cables very separate from power cables and so forth.  What
> are the implications of bundling all cables together on a computer?

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First, my credentials.  I am a retired electrician with over 45 years experience
as a journeyman, a contractor, an instructor in apprentice and journeyman
training programs, and so on.  I am well aware of the problems you mention in
regard to audio cabling to minimize interference.
In my opinion they do not make an appreciable difference in the present
discussion.

The only truly measurable amounts of current flow (which is the direct cause of
the magnetic fields that cause interaction between circuits) are in the power
cables to the computer itself and the monitor.  Those current-carrying wires are
enclosed in close proximity in a cord, and the opposite direction of current flow
cancels the external magnetic field to a great extent.  Example:  A clamp-on
type meter cannot reliably measure the current through a cord; the two current-
carrying conductors must be separated and the clamp placed over one of them
to measure current.

All the other cables (mouse, keyboard, video signal, speaker wires, scanners,
printer data cables,) etc. have minimal current flow, and that flow by no means
constant, therefore minimal magnetic fields to affect other circuitry.

The low signal levels in unshielded audio cables used in sound systems are
much more susceptible to cross-talk and power line interference in part
because of the extended length of the proximity of wiring systems.

That does not seem to apply to digital signal systems to any great degree.  I
have seen installations where hundreds of feet of Cat-5 cabling for 10 baseT
and 10/100  systems were in close proximity, with no apparent ill effects.

I will be interested in follow-ups.

Don Riggs



       I love cats . . .they taste just like chicken.

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