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Re: Ribbon Cables

From: "R. Paul McCarty" <>
Date: Wed, 15 Apr 1998 12:36:41 +0000

The obvious problem is time delays; the higher the clock speed of your
bus the shorter it has to be in order for the electrical signals to
cross the bus in a single clock cycle. So, for a 66MHz bus to function,
signals need to traverse the bus in t=1/f or 15ns, assuming electricity
flows at close to the speed of light 3x10^8 m/s, length=(3x10^8m/s x
15x10^-9) = 4.5meters.  But my guess is this is the theoretic upper
limit, and its probably alot less than that due to things like
capacitance between wires, resistance, and the like, but it can probably
be extend a foot without any problem. 

I looked for pc/104 bus cables, but didn't see any online. Suppose you
could always solder one together.

-Paul

Glen Johnson wrote:
> 
> > > does anyone know of a source that can provide cables to remotely mount a
> > > PC104 card from the base stack?
> >
> >  I haven't seen them, but they could exist. There are many problems inherent
> > in extending the bus, though.
> 
> I thought of the same thing, can someone comment on this?  Like how long
> can a bus be extended?  Why is there a restriction-- low voltage/signal
> degredation?  What other problems?  I seems like cabling the bus would add
> a lot of flex to the entire setup.
> 
> glen

-- 
R. Paul McCarty / DARS Coordinator /  / x52059
317 Lattimore Hall, University of Rochester, Rochester, NY 14627
Computers don't make mistakes;what they do,they do on purpose.-Dale/KOTH

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