The EAP seem to use 24V "passive PoE" and normal PoE is to my knowledge running on (optimum of course) 48V, realistic between like 37,42-57 (depending on the standard, PoE or PoE+, ++...), so I think that might be issue..

I think TP-Link did it on these models since they need a lot of power on one hand but on the other hand that high voltage generates a lot of heat when converted back to like 12 or 24V so that might be the reason why they did it, but if possible why not use a PoE dejector at the end that makes out of your PoE one Ethernet and 12V connector so you can use it normal.. I did that to make e.g. my Smart Home Laptop (just an old laptop with android x86) using PoE even if it does not support it.

That is like from the "Deutsche" Telekom their Speedport ISDN converter that only works with a speedport router, just to make it easy to use.. same is basically here, if it gets to warm it does not work well so they put down the voltage to generate less heat when using PoE, but that dejector should work at all, I have here 4 running..

  @Julian2111 

Interesting approach. Indeed, I have not seen this kind of workaround. Normally used to power non-poe devices. But you are right, this could also solve the incompatibility between two different poe voltages. 

However, as these EAP211 are outside, these adapters would need to be made waterproof. 

What I do not understand, all the products are coming from the tp-link universe (even only business products), not mixing vendors, and are still incompatible, if you are right. 

  @Vincent-TP 

Thanks Vincent, however this is not "solution" a customer likes to hear. From my point of view this is not really satisfactory. If a product is shown as new on the website, I assume that it also supports "new" features, like being integrable in existing PoE environments.

As PoE inductors kept stacking in my rack, what really was a mess, I connected all of my EAP245s, EAP615s and my EAP225 to the PoE Switches. So now, again, I have an inductor, which has no place in my rack, which is lying on top of it 

However, thanks for the explanation. And please, communicate this back to your development teams, that such a "solution" is not satisfactory, and they should come up with products which are better integrable into their own product universe.