PoE Power Requirement on the "Wrong" Port of 4P-PoE

BenjaminKiefer

Hi!
We use the 4P-PoE camera board and usually power it via a PoE port on a custom Nvidia Orin AGX. This port provides 25.5W.

Now, we wanted to switch to another AGX without PoE option and we're looking at several switches. We noticed that when using the "proper" port on the cam board (as described here), many PoE switches work. However, due to our CAD design of the casing, we have to use the other port, which worked as well with the original AGX (25 Watts), but not with the switches we tried.

Now, I wonder what the power requirements are in the case of powering the camboard through that port. Is it supported at all?

I know about the supported switches, but I'm not sure if they work for both ports.

Hope that makes sense, thanks!

jakaskerl

BenjaminKiefer
You are trying to power the 4P-POE via ETH OUT port if I understand correctly?

BenjaminKiefer which worked as well with the original AGX (25 Watts), but not with the switches we tried.

And it worked when the POE was supplied by AGX? Seems strange, but would have to ask the hardware team.

Thanks,
Jaka

BenjaminKiefer

Thanks @jakaskerl, yes correct. It also worked with the PoE injector as given here:

https://shop.luxonis.com/products/poe-injector?variant=43731965673695

jakaskerl

BenjaminKiefer
Apparently it was possible on earlier generations of 4p-poe since we had passive POE output (so any voltage level would do). Newer generations have onboard chip that performs the negotiations so this is no longer possible.

Why this was possible on jetson? Probably for the same reason. Reverse powering was possible due to passive POE. I'd guess that switches and injectors are not compatible with it, but jetson was.

Thanks,
Jaka

BenjaminKiefer

jakaskerl

Thanks, do you think this might become an issue with certain pipelines in view of stability or performance?

jakaskerl

BenjaminKiefer
No, it would depend on the POE source.
Though I must advise you not to plug in both POE ports (with power IN) at the same time since it creates a voltage difference somewhere down the line and can potentially fry your circuits. That's why we added active POE negotiations.

Thanks,
Jaka

BenjaminKiefer

Ok, thanks!