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"Bad cable or end"
Posted: Fri Jan 20, 2017 2:02 pm
by roaoro
After spending hours troubleshooting and replacing cable, ends, and equipment, I'm finding there is no problem as the cable test suggests. Why is it telling me there's a problem on our M radios if there's not?
Re: "Bad cable or end"
Posted: Fri Jan 20, 2017 2:26 pm
by Julian
What do the diagnostics say if you run them without a cable in the port?
Also, please include the model number and firmware version with your response, it will help me be of more assistance.
Re: "Bad cable or end"
Posted: Fri Jan 20, 2017 2:36 pm
by sirhc
OK maybe you should read this post:
viewtopic.php?f=6&t=1178 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.
All airMAX M radios will always report short on pair 3 and 4 which technically is NOT standard and will report bad as ubnt shorts the pars together not following the standard.