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Re: OT question sorry but i need salution fast ....



On Thu, 13 Jun 2002 00:47:17 -0400, Anthony DeRobertis wrote:

>
>On Tuesday, June 11, 2002, at 02:14 , faisal gillani wrote:
>>
>> well i have 2 ethernet networks running which i want
>> to connect but the distance between them is above 400
>> meters .. so this is way beyond the normal lan
>> hardware ..
>
snip
>The only thing that will 
>stop you[1] is if the signal is not strong enough on the other 
>end, or the noise has won. Amps might help, as would lower gauge 
>wire. I'd be interested in hearing how how far you can get away 
>with cat5.

This strikes me as an RF transmission line problem.  Twisted pairs
(cat5) are a reasonably low loss transmission line at audio and low rf.
At 1 gHz they become very lossy. (I know, we're not talking more than
100 mb/s, but these are square waves which have high value odd harmonic
components---3rd, 5th, 7th, 9th, and etc overtones.)  Since these
harmonics are attenuated more than the fundamental (a transmission line
is a low pass filter), the effect is to slow the rise and fall times of
the wave form.  This may cause the detector to mis-read the signal.
Unless active devices are used to regenerate the wave form within
acceptable loss-distance,  _very_ high quality (read air dielectric coax
(hardline), or balanced twin lines) transmission lines are necessary.

snip
>[1] Before someone starts yelling collision domain, remember I said
>     'full duplex'. There should be no collisions, and hence no
>     problematic late collisions.

Thus, dual transmission lines, native to cat5.
--
gt
Everything here could be wrong--Messiah's Handbook--Bach


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