I've got a hEX S up and running on my network, and I've been trying to sort out the option of powering it by the 48V POE injector that I already had. I carefully checked that the POE injector does carry the voltage on the same pairs as Mikrotik is expecting, voltage within spec.

Here's what happens: with the router off, plugging POE out on the injector into port 1, the router does not power on. The power LED flashes, along with the light on the side of the injector. What I've gathered is the flashing means that the injector cannot negotiate what's on the other end. This is 48V passive, but apparently there is still some kind of checking going on.

I have also tried plugging in POE once the router is running under its own 24V power supply. The router sees that and changes to use POE. At that point, it can also provide POE on port 5 to my AP. I can even unplug the 24V power supply and things keep running. Even to the point where restarting in winbox has no problem. But if I lose power for any reason, it seems that I cannot get things running again with just the injector, I have to "jump" the router with its power supply.

I've seen a couple old threads that might have alluded to a setting on ether1 that would adjust the power negotiation coming in. I'm not sure if that may have been for a different product, or older version of RouterOS, because I can't find anything in Winbox. Is there a setting for anything like this that I've missed?

Thanks.

RB760iGS wants standard, 802.3af PoE..

Then it will work without issue.

Is the passive POE specified in the user manual (and printed on the case) not really supported? Even if it is, it could just be that the particular one I have is not really compatible. I take it there's nothing to adjust in RouterOS to try to get things to cooperate?

I may pick up an 802.3af injector sometime to try it. Or better yet might just buy the Mikrotik 48V power supply for the setup. This was my original plan, just wanted to try without first.

Of course oddly enough, the setup that I said was running fine started losing the POE power, and I had to restart things a couple times. (right after posting, haha) So I've now changed back to powering the router on its own, with the POE injector directly to the AP.

https://mikrotik.com/product/hex_s

PoE in 802.3af/at
PoE out Passive PoE up to 57V

The RB750Gr3 is passive PoE in.

It does say passive in the user manual:
https://help.mikrotik.com/docs/display/ ... g-Powering

The first Ethernet port accepts passive or 802.3af/at Power over Ethernet in the range of DC ⎓ 12-57 V.

Also stated this way in the brochure, and directly on the enclosure. Either way, I guess in reality it seems that mine is not fully compatible anyway.