Min lenght for patch cable

Is there a minimum length for a patch cable? I think I found somewhere a text saying that the limit is 3 ft, but for the life in me I can't find the reference

Thanks SP

Reply to
Sparanghel
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I've seen them as short as a couple of inches. worked fine.

--Dale

Reply to
Dale Farmer

I've made them 6 cm wirelength to cross over two interfaces in the same machine. Ran fine. This is far more demanding than the typical patch panel that has 100's of feet of total wirerun.

My shortest is a single loopback plug. 2 cm wire. Also works fine.

-- Robert

Reply to
Robert Redelmeier

Finally I found the reference. Is not very conclusive:

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Remember, an end to end connection should extend at least 1m (3ft) and not more than 100m (~328ft). Yes, there is a minimum, its little known, little referred to and not usually important, but I have seen cases where short cables caused problems. The longer the cable becomes the more it may affect performance, usually it is a gradual decrease in speed and increase in latency. When uplinking between (cascading) hubs/switches, you usually need a very short cable, less than 1m, check the device's specifications. SP

Reply to
Sparanghel

I'm deeply suspicious of a reference with homebrew information.

"gradual decrease in speed"? never seen. I've run overlength cables at full wirespeed.

"increase in latency"? Only theoretically. A full 100m roundtrip takes 0.0010 milliseconds.

Cascading 100baseTX hubs (if you can ever find one) is subject to very tight rules to respect the collision diameter. 10baseT has the old 5-3-1 rules. Switches aren't subject to these cascading rules.

Perhaps the author has seen problems with short cables. With homemade crimp-on-solid I'd expect problems.

-- Robert

Reply to
Robert Redelmeier

Whatever the length of the cable. Though some people just don't appear to understand why putting crimps on solid cable is a bad idea.

Reply to
Mark Evans

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