Hello!
Please answer only if you are an expert

I have a MikroTik RB3011 UiAS-RM, which has an Ether10 port that supports passive (PoE) output. This port has an auto-detection feature and operates at a voltage of 24V, outputting approximately 2V below the input voltage(22V) but it doesn’t support with IEEE 802.3af.
On the other hand, I also have a Ruijie RG-RAP6202(G) which supports the IEEE 802.3af/802.3at PoE standard and operates with a power supply of DC 12V/1.5A.
I know it is not logical to connect them but might be something I’m missing, so I’m asking to know, would it be safe and feasible to connect the Ether10 PoE port of my router to the Ruijie RG-RAP6202(G) PoE Lan port

thank you

Nothing will happen, RB3011 will not see compatible device and will not output power to it. Be careful not to have PoE forced on, then it will output 24V all the time.

Also, to be extra safe you can disable PoE on port 10.

supports the IEEE 802.3af/802.3at PoE standard and operates with a power supply of DC 12V/1.5A.

Correct not and, but or.
Your device is powered by a 12V power supply or 802.3af/802.3at 48V .

Thank you for your clarification .

Indeed, the device can be powered by a 12V power supply or 802.3af/802.3at. The 12V likely refers to the DC Port, and the 802.3af/802.3at isn’t specified because it’s a standard.

Given that the 802.3af/802.3at operates at 48V, and the device’s reception range is higher than what the 3011 port provides, it should be safe to try powering the device via PoE. However, due to the lower power source, its performance might be negatively affected.

Initially, I was concerned about a higher voltage, but now I’m considering the implications of a lower one.

Any further suggestions are welcome

Thank you both again.




Ruijie RG-RAP6202(G)

If it is below 44 V or so it is not anymore 802.3af or at.
Forget about that standard.
Besides the voltage level it implies a negotiation between the PSE (Power Sourcing Equipment) and the PD (Powered Device) that simply won't happen if any of the two are not compatible with the standard:
https://versatek.com/poe-negotiation-of ... -protocol/

You have a passive output that provides theoretical 24V that are 22V in reality.

There are PoE splitter/converters that can extract the 22/24 V and convert them to 12 V, your device evidently needs 1.5A@12V so you want one capable at least of 2A, as you are already 10% low..

The common ones are usually 1A or a little more (they are used often for IP cameras), but the 2A do exist, example:
https://www.aerial.net/shop/product/22_ ... a-out.html

You need one that - just like the Mikrotik - use Mode B, i.e. uses wires 4,5 for the + and wires 7,8 for -/ground:
https://help.mikrotik.com/docs/display/ROS/PoE-Out

Nothing will happen, RB3011 will not see compatible device and will not output power to it. Be careful not to have PoE forced on, then it will output 24V all the time.

Also, to be extra safe you can disable PoE on port 10.

Driven by curiosity, I couldn’t resist the urge to test the connection myself. I noticed that the power status on the RB3011 was indicated as ‘ON,’ but unfortunately, the Ruijie AP did not power up. Luckily, no damage occurred. I scoured the settings for any relevant options that might address this issue, but to no avail. It seems that this is the end of the road for this experiment. Thank you all for your input and assistance.

There are PoE splitter/converters that can extract the 22/24 V and convert them to 12 V, your device evidently needs 1.5A@12V so you want one capable at least of 2A, as you are already 10% low..

2A on 12V side shouldn't be necessary, device requires up to 13W which is 1.1A@12V. But I fear there's another problem: PoE out on RB3011 is rated at 0.6A and even if power converter would work at 100% efficiency (which it doesn't) it would work at limit.

You need one that - just like the Mikrotik - use Mode B, i.e. uses wires 4,5 for the + and wires 7,8 for -/ground:
https://help.mikrotik.com/docs/display/ROS/PoE-Out

Thank you for the detailed explanation. It seems that a PoE splitter/converter capable of at least 2A would be necessary to adapt the MikroTik’s 22V output to the Ruijie device’s 12V input. I’ll ensure to choose one that uses Mode B wiring to match the MikroTik’s setup. This should safely bridge the compatibility gap between the two devices.

2A on 12V side shouldn't be necessary, device requires up to 13W which is 1.1A@12V. But I fear there's another problem: PoE out on RB3011 is rated at 0.6A and even if power converter would work at 100% efficiency (which it doesn't) it would work at limit.

Yep, it is right around the limit, might be just enough, 0.6A@24V=14.4W, but 0.6A@22V=13.2W, not enough considering some dispersion in the conversion and possibly on the length of cables.
I suspect (but I may be wrong) that the common 1A@12V splitters are already at their limit, if one can find a 1.5A@12V one it will be fine, but I have only seen 1A and 2A (or more) ones.

It might be needed to change the power supply to the Mikrotik in order to raise a little bit the voltage (up to 30V can be used), possibly a 28V 1.5A or 2A would be suitable.

I'd ditch the idea of using RB3011 PoE out and go with stand-alone solution. One possibility is to use MT's RBGPOE passive PoE injector and 48V power adapter ... Ruijie might just start (the handshake part of 82.3 af/at standard is for PSE to make sure there's a 48V-capable equipment at the other end not to cause damage) while many PDs don't insist on doing it and just power on when they receive 48V power.

@OP ... if you'll pursue this idea, do it on your own responsibility.

@all thank you