[SWLUG] Interesting cabling puzzle

[Mark Fisher]

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On Tuesday 03 Jun 2003 9:51 am, Gareth Bowker wrote:
> On Tue, 2003-06-03 at 00:43, Rhys Sage wrote:
> > I've run across a real rum one here!
> >
> > I have a long (15m) cable running from my Linux box to my PC with a
> > crossover at the Linux end.
> > The crossover is of the female socket with male plug type (RJ45). That
> > works fine.
> >
> > I take the crossover out and put a short (0.5m) cable into the Linux box
> > and put a double-socket RJ45 crossover in and nothing happens. The NIC
> > lights don't come on. I try a different short cable (1m) and nothing
> > happens. I try the f/f crossover at the PC end and still nothing happens.
> > I change the f/f crossover and still nothing happens. I even tested the
> > f/f crossover to see whether it was a crossover or a straight through
> > connection by putting the m/f crossover on it. Still nothing happens.
>
> Umm, pardon? You lost me somewhere in the second paragraph. Can you
> provide some ascii diagrams or something to help follow what you're
> saying. e.g.
>
> Computer-> straight cable-> crossover box-> straight cable-> computer

I know what you mean, on the 3rd reading I sorta got a mental picture tho :P

> or whatever. What exactly are these crossovers you're talking about?
> I've only ever used cables that had the crossover built-in so I've not
> used what you're talking about - what are they, exactly?

A box with 2 holes, doing as you described.

> If the lights aren't coming on on the NICs it's a wiring problem
> somewhere most likely.

Agreed, so far we know that the original crossover box and the 15m cable do 
their job properly.  Unless I missed something, the story didnt mention about 
how the other cables did with this box, or in fact the 15m cable did with the 
other crossover boxes.

Did I miss something?

> Gareth

- -- 
	Mark
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