MikroTik

I have a RB200 up a tower using PoE. It runs fine until I try to connect a device to the data port of the PoE injector, then the power to the RB200 shorts and the router goes down.

Strangely I can plug in my laptop ethernet port but not an ethernet switch or other device.

I've double checked termination and a cable tester says the cable seems OK.

Any ideas?

Trisc

So the router is off, you plug it in and it shorts?

Or is there something I am missing?

No router is on, until I connect something else into data port on the PoE supply.

OK. Now I understand.

You stated it just fine, I read it wrong.

Have you tried using a cable where the power pairs are not terminated? If that makes it work, then your injector may be feeding power out both sides.

A VOM could tell you the same thing.

which pairs carry power?

we had a static electricity storm 15b days ago and the 2 rb230 in a tower stopped working. So we went there and we had the same as you:

1- the poe injector had the green (the only light) blinking at a cosntant pace
2- but unplugging the cable of the LAN and leaving the poe, the light stopped blinking and stayed normal
3- with my laptop directly connected to the injector it worked fine
4- if i put back a switch conecte to lan than the rb230 stops working

this was so strange that it took some time before deciding changing it to new rb.

did you find out the reason so far ?

ciao
Gianluca

If you are using standard 568-B the brown pair carries the power.

I had a similar issue, I asked the user to unplug the router and plug it back in at the mains socket, for some reason he unplugged the ethernet cables and then plugged them in the wrong way round so the poe side went to the switch. We had to change the switch to get things working normally again. The old switch works fine in its new environment (which doesnt involve poe)

this is a little bit different since it involves a swicth demaged by poe.

Thats true, i only mentioned it as the symptoms are the same and thought that some voltage surge or something could have damaged the switch that he is connecting to

Sounds like PoE has gone away. Did you try with another PoE couple ?

of course I tried with another poe splitter. Cable is ok since we changedthe RB and worked fine with new one.