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Re: Cat 3 cabling

On Fri, Oct 24, 2003 at 11:45:26AM +0200, Nicolas Bougues wrote:
>On Fri, Oct 24, 2003 at 03:27:32AM +0800, Jason Lim wrote:
>> So in essense, since they are both 4-pairs, just looking at it won't let
>> you know which it is (without actually testing it)?
>Right. And furthermore, even "testing" with 100 Mbps Ethernet
>equipment is not the right thing to do.
>> Any way to turn Cat 5 into Cat 3, and vice versa?
>Cat 3 is ok for 10 MHz signal, Cat 5 for 100 MHz. There are of course
>other paramters in the spec, like signal attenuation, isolation,
>etc. There are devices to certify cables, such as Fluke Networks
>tools. They are not cheap, though ($5000 +).
>Simply put, don't use Cat3 for Ethernet. Use Cat 5. Or, since Cat 5 is
>deprecated, Cat 5e, which is 100 MHz too, but with enhancements. Or
>Cat 6 (250 MHz), or Cat 7 (500 MHz, I think). But then you need to be
>rich :)

depends what you are doing. I was given a box of cat3 8" (maybe 10"?)
lengths. In my super sophisticated tests, there was no difference (and
surprising similarity on each test) comparing cat5 in time to transfer
something like a 1gb through a 100Mb switch.

I've been told longer runs would bring out the problems of interference
either from the signal in the wire or external sources like fluorescent
lights etc.

Determining one from the other, my cat3 is about 75% the diameter of my
cat5. can also see the twists and braids through the insulation of the
cat5 which I understand limits radio interference. I would guess the
cat5 is of higher gauge too.

so use cat3 for ethernet? can't advise it but if you have some on hand
it may suffice; don't stretch, fold or otherwise push it, also concider
the cost of data loss, downtime and rewiring, should you find the need
to rewire.

// George

GEORGE GEORGALIS, System Admin/Architect    cell: 646-331-2027    <IXOYE><
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