Netonix Forums

http://imgur.com/sYKksA2

According to this the cable shouldn't work and should blow something up. I used the cable with the AC POE the AF5x came with and had no problems.

I went ahead and turned 24v on (there is no VH on port 8) and the AF5x came up just fine.

You upload your pictures to the forum not put a link to them.

To upload a picture click the upload attachment below the blue submit button.

Read this post (the Q&A at bottom): viewtopic.php?f=6&t=1178

sirhc wrote:You upload your pictures to the forum not put a link to them.

To upload a picture click the upload attachment below the blue submit button.

Read this post (the Q&A at bottom): http://forum.netonix.com/viewtopic.php?f=6&t=1178

Uploaded via forum

What you will find is when you run cable diagnostic on an unpowered device you will get weird answers depending on how the device is designed which will affect the results.

What you NEVER want to see and NEVER turn POE power on is when you see a "CROSS SHORT".

Shorts on a pair is not necessarily always bad and in some 10/100 devices is expected on pairs 3 and 4.

I always tell people to LAB all their devices and write down how they report before you apply power then how they report after you apply powers.

For instance some 1G devices may report a short or abnormal termination on a pair until you apply power then the report OK on all 4 pairs when powered.

Some Ethernet Surge Protectors can really mess up cable diagnostics.

I suspect my original post wasn't clear. I just had the cable plugged into the switch, there was no radio or anything on the other end of the cable.

jluthman wrote:I suspect my original post wasn't clear. I just had the cable plugged into the switch, there was no radio or anything on the other end of the cable.

Then 1 of 2 things is BAD:
1) Your cable is bad with pair 4 shorted which you can test by running the cable diagnostics with the cable in another port and if you get the same results you have a bad cable.

2) You have a damaged Ethernet Transformer which you can verify by running the cable diagnostics with no cable plugged in. If you still see a short on pair 4 with no cable you have a damaged Ethernet Transformer which we can repair for a fee if you RMA it. This is most often caused by applying POE to a shorted cable or incompatible device.

Pair 3 or 4 can be shorted and you could still get a 10/100 link but not a 1G link.

Moved cable from port 8 to 12 and the symptoms followed the cable, port says open with no cable.

I don't understand how the cable can work for 4 pair power and gigabit if it's bad, though?

jluthman wrote:Moved cable from port 8 to 12 and the symptoms followed the cable, port says open with no cable.

I don't understand how the cable can work for 4 pair power and gigabit if it's bad, though?

Show me a cable diagnostics with the device powered up because the diagnostics below is NOT with the device powered up.

The cable diagnostics will be different with the device powered up or down.

Running cable diagnostics on an unpowered device will give weird results due to the way the device is made and how the test works so it will vary from device to device.

Once the device is powered up it should be OK on all 4 pairs but the diagnostic above can NOT be from a device that is powered up and linked at 1G but can be from a device that is not powered up.

With the device powered on it is all OK (see attached).

It just seems to me that if cable diagnostics comes back with a "bad cable" even though it isn't, the only solution is to use an AC POE to test the line is good.

jluthman wrote:With the device powered on it is all OK (see attached).

It just seems to me that if cable diagnostics comes back with a "bad cable" even though it isn't, the only solution is to use an AC POE to test the line is good.

Did you read the posts I suggested earlier????
viewtopic.php?f=6&t=1178
viewtopic.php?f=6&t=1868&p=13896&hilit=+cross+short#p13896
viewtopic.php?f=17&t=1734&p=12998&hilit=+cross+short#p12998
viewtopic.php?f=6&t=1702&p=12796&hilit=+cross+short#p12796
viewtopic.php?f=6&t=1215&p=10941&hilit=+cross+short#p10941

It will explain why diagnostics behave differently on un powered devices.
The only thing that is BAD on an unpowered device in a cable diagnostics is a "CROSS-SHORT"

Here are some good posts on grounding:
viewtopic.php?f=30&t=1816
viewtopic.php?f=30&t=188
viewtopic.php?f=30&t=1429
viewtopic.php?f=17&t=1786&start=30#p13447
https://community.ubnt.com/t5/airFiber/ ... rue#M31070
The forums will answer most all questions if you search for answers to questions and do some reading.