I'm wondering how accurate cable diagnostics are.
I'm seeing this result even after putting new ends on a cable.
Pair 1 Status
Ok
Pair 2 Status
Ok
Pair 3 Status
Short
Pair 4 Status
Short
Pair 1 Length
29.53
ft / 9m
Pair 2 Length
29.53
ft / 9m
Pair 3 Length
19.68
ft / 6m
Pair 4 Length
3.28
ft / 1m
How accurate are cable diagnostics?
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sirhc - Employee
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Re: How accurate are cable diagnostics?
Cable diagnostics is pretty accurate but somethings can throw it off like things like Ethernet Surge Protectors, stretch or kinked wires, bad ends, and some devices.
There are many posts I made about this, here is one: viewtopic.php?f=6&t=644&p=4604&hilit=stretched#p4604
Some devices on the other end will cause cable lengths to be reported incorrectly when they are plugged in but not powered up.
As far as seeing this:
OK
OK
SHORT
SHORT
This is normal with any ubnt airMAX 10/100 device as they have pairs 3 and 4 shorted together to carry POE power.
As far as pair lengths being reported different that can be caused by 3 things:
1) Cable was damaged during installation, it was stretched or kinked
2) Some devices when not powered up will cause pair lengths to be reported incorrectly.
3) Ethernet Surge protectors - results vary depending on unit used.
Why not search for all the posts you can find on this issue searching for things like "Cable Diagnostic", "cable test", and such as I have done some LONG WINDED posts on this already.
There are many posts I made about this, here is one: viewtopic.php?f=6&t=644&p=4604&hilit=stretched#p4604
Some devices on the other end will cause cable lengths to be reported incorrectly when they are plugged in but not powered up.
As far as seeing this:
OK
OK
SHORT
SHORT
This is normal with any ubnt airMAX 10/100 device as they have pairs 3 and 4 shorted together to carry POE power.
As far as pair lengths being reported different that can be caused by 3 things:
1) Cable was damaged during installation, it was stretched or kinked
2) Some devices when not powered up will cause pair lengths to be reported incorrectly.
3) Ethernet Surge protectors - results vary depending on unit used.
Why not search for all the posts you can find on this issue searching for things like "Cable Diagnostic", "cable test", and such as I have done some LONG WINDED posts on this already.
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adairw - Associate
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Re: How accurate are cable diagnostics?
It's pretty typical for the pair length to be slightly different even in perfect cable.
I ran a Fluke DTX-1800 on many a cable and they almost never come out the same length.
Mostly because that's the wait the cable is designed. If you look closely there is a different amount of twist for the pairs. This makes some longer and some shorter.
I ran a Fluke DTX-1800 on many a cable and they almost never come out the same length.
Mostly because that's the wait the cable is designed. If you look closely there is a different amount of twist for the pairs. This makes some longer and some shorter.
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