Cable test ubiquiti m900

[talleytech]

I am having some issues with the cable test on a Netonix mini switch connected to a Ubiquiti M900. I get the same results with or without power. The test shows



Pair 3 Status (Pins 4,5) (Pos) (Blue)
Abnormal termination


Pair 4 Status (Pins 7,8) (Neg) (Brown)
Abnormal termination




I replaced the ends on the cable before I replaced the 137 feet of cable. I also replaced the radio with another used radio but works fine. I tested the cable with a cable tester and it shows it test good. I have had issues with the cable tester so I don't really trust it and I really like testing from the switch. The length is also off on the 3rd pair by 3 meters or just short of 10 feet. I am leaning toward the issue being with the radio but I don't understand why 2 of the same types of radios would test the same way even after replacing the cable. After it tested bad with the new cable I did replace the ends again with the same results. I am using Netonix shielded ends and ubiquiti tough cable pro with the shield pulled over the jacket of the cable. I wonder if there is a known issue with testing from the netonix ws-6-mini switch on the Ubiquiti M900? Any suggestions would be greatly appreciated.
Thank you,

[sirhc]

First I moved your post from "TOWER" Switch to "WISP" Switch as we are not selling a Tower Switch yet.

I did a search for your question and foind this post(but there are many more to read through if you like or feel you want more information):
viewtopic.php?f=6&t=1178#p8809

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Question: Why do I see abnormal termination when I do a cable diagnostics?

Answer: Because every manufacturer does not follow the proper design specs so when the device is unpowered it is actually doing the cable test into the device electronics and every device will report differently. They "should" report OK, OK , OK , OK once the device is powered up however some Ethernet surge protectors will always report abnormal termination.
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Question: Why do I see short on pairs 3 and 4 on a of devices especially UBNT airMAX 10/100 gear.

Answer: Because every manufacturer does not follow the proper design specs and use a 4 channel Ethernet Transformer designed for POE with a center tab for each pair. Since pair 3 and 4 is not needed to carry data with 10/100 only links they use them for power only which allows them to use a cheaper 2 channel transformer without a center tap for pairs 1 and 2. They then connect the 2 wires from each pair to the board skipping the need for a transformer with a center tap so the 2 wires from pair 3 are connected directly to the board shorted together for positive and the 2 wires from pair 4 are shorted together directly on the board for negative.
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Are you using a surge arrestor?

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Question: Why do I see abnormal termination when I do a cable diagnostics?

Answer: Because every manufacturer does not follow the proper design specs so when the device is unpowered it is actually doing the cable test into the device electronics and every device will report differently. They "should" report OK, OK , OK , OK once the device is powered up however some Ethernet surge protectors will always report abnormal termination.
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[talleytech]

Thank you for helping me with this. No surge protection on this one. I did try the test with and without power with the same results. It doesn't show short or cross it just says abnormal.

[sirhc]

Thank you for helping me with this. No surge protection on this one. I did try the test with and without power with the same results. It doesn't show short or cross it just says abnormal.

This means one wire in pair 3 or 4 is not carrying power.

Pair 3 and 4 are not used for 10/100 communications.

Re-Crimp your ends nor you have bad cable

[lligetfa]

I tested the cable with a cable tester and it shows it test good...

It's not uncommon for an overcrimp to pass in a tester but fail in situ. Many testers have very high quality RJ45 jacks in them since they are reentered so often. The jack in the radio is not high quality.

[talleytech]

I will order a new radio and test. If it don't pass I will replace the end that goes in the M900. It's so odd that it has tested the same way on 2 different radio and new cable and ends. Thank you for helping me with this issue. I will let you know the results after a couple days.

[sirhc]

Well use your head and a little deductive thinking and figure it out.

You say you have another radio that yielded the same result so........

Use a PREMADE JUMPER you know is good and plug the other radios in another port on the switch and power it up and run cable diagnostics on it.

If when powered you get OK, OK, SHORT, SHORT then you know it is the cable right?

Learn to use what tools you have at your disposal at think outside the box.