I have an old 5548P that I'm trying to add to my current stack. I have an Ubiquiti ER-X that I'm trying to supply power to over PoE, but I'm not getting anything.

  • The ER-X pulls 5W, and a port on the 5548P can provide up to 15W, so it's not a supply issue.
  • I've done a complete reset and updated the firmware.
  • The ER-X powers up fine when supplied with power from the wall.
  • I've disabled per-port energy consumption conservation per the manual
  • I can see that the device appears as active in the port list as a class0 device.
  • The PoE indicator light is solid amber, meaning that power is being delivered.

I'm honestly not sure what the issue could be. Any suggestions?


2 Answers 2


I'm dumb and didn't think of the voltage coming from the switch. An adapter is needed to transform 48V from switch to 24V.

  • 3
    I was going to say, the Ubiquiti devices often had non-standard PoE injectors that they came with or required. I'm not sure about the latest generation ones but models from a few years back commonly needed special power supply equipment. Commented Jan 10, 2023 at 3:19

Ubiquiti is very loose with the term PoE.

The ER-X uses a proprietary 24V variant (as PD and PSE). It's not compatible with IEEE PoE as provided by the PowerConnect 5548P.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.