Hi guys,

Just configured my new RB5009UPr, migrated from RB4011.

I was trying to power a ONT (Ubiquiti NanoG - 24v passive poe which I have had for years with RB4011) via eth1 with PoE but when I plug int the erthernet cable I see "voltage too high" in the ethernet1 interface.

In addition, once I noticed this behaviour, I triet to plug in the RB5009 with PoE-in and it seems to be that eth1 is the only port which boots the RB50009 up. If I try with the other ports, nothing happens.

What is going on with PoE management of these boards? I am in 7.8rc2.

Any support appreciated. Regards

Going deeply after some tests:

- Power brick output is 48v whic is bypassed to the PoE-outs so NANOG is 24v passive, it can not handle it. Is there any possibility to plug a 24v adapter instead of 48v?

- PoE-in only works in port1 (eth1), there is no response when I plug PSE in any eth2 to eth8 ports.

Any advice?

I think product page has all the answers:

• input voltage range for RB5009UPr is 24V-57V.
  So yes, you can use 24V power supply. It's on the lower edge of allowed range so device might get unstable if voltage drops below 24V (if power brick won't be able to sustain the load ... my advice is to get a pretty beefy power adapter ... above the required power)
• "What about the PoE-out devices? Once again – the highest voltage wins."
  Meaning that if you want 24V PoE out, none of power inputs should be higher than that. Including PoE-in.
• support for PoE-in: 802.3af/at (ether1), Mode B (ether2-ether8)
  In theory powered device (if truly 802.3 af/at/bt compliant) should support both mode A and mode B and it's up to power source equipment to choose which one is going to be used. With limitation stated RB5009UPr becomes non-compliant device on ports other than ether1 and that itself will upset 802.3af/at/bt PSE... Passive PoE power sources which only work in mode A won't be able to power this device via ether2-8.
  So either use passive PSE which works in mode B or use barell plug as powering option of RB5009 ... The later is IMO the only right way if device is being used as PSE for further devices (after all, 802.3 af/at/bt and most passive PoE injectors all come with power limits which don't allow powering too many "slave" devices).

So I've run into the same issue with my RB5009UP and a brand new and shiny hAP ax³. This one only supports up to 28 V of input. It works when powered by a CRS328-24P (which then spits out approx. 26 V). Are there any recommendations for a suitable PSU with ideally 28 V? Looks like there are lots of 24 V options, but I'd like to use as high a voltage as possible to keep current low. TIA!

Just put 24V PSU... Current difference is negligible and its much easier to find 24V PSU.

Yeah, that's what it seems like. So I'll probably use one of those 24 V LED PSUs with voltage adjustment. Those can be bumped up by 10 %. Close enough.

.... I'd like to use as high a voltage as possible to keep current low.

If your PoE cables are not really long (to cause significant power losses), then you're probably loosing more on internal DC-DC downconverters (inside PoE-powered drvices), their efficiency gets lower with increased difference between input voltage and required voltage (which is nowdays lower than 5V).