For cAP lite
Look this (Brochure): https://i.mt.lv/routerboard/files/cAP_l ... 135711.pdf
& look this * (Quick Guide): https://i.mt.lv/routerboard/files/cAP-L.pdf
*Powering
The device accepts powering from Ethernet port (Passive PoE only). Under maximum load, the power consumption of this device is 4W

What the truth ?
What kind of POE support ?

According to its specific brochure, dated 10th April 2017 (manual is dated on 30th Nov 2016)
It does support the three options: Passive, at and af.

Yes, it works with 802.3af/at

You can always refer to this page for specific details:
https://wiki.mikrotik.com/index.php?tit ... lity_table

Sorry to refresh this thread. I've bought a cAP lite thinking to use a Netgear GS108T-200GES or a Tenda TEF1105P-4-63W. This because I need to set up a wireless system at school with a very low budget. Unfortunately neither the first nor the second switch is powering the cAP using a direct or a crossover cable. Based on the wiki I was assuming that at least using a crossover cable the cAP was adherent to 802.3af, but nowadays seems not. Does Mikrotik has any cost effective (I mean that costs less then Ubiquiti) AP with full 803.2af support?

The CAP lite does not power up using a Tenda TEF1109P or TEF1105P, even though both switches supposedly complies with the 802.3at/af standard.
Can anyone explain why the CAP lite won't work with all switches that uses 802.3at/af?

The same problem, mAP lite doesnt work via PoE in with TP-LINK TL-PoE150S, D-link DES-1018MP, D-link DGS-1008MP.
Please help

I had the same issue trying to power up a cAP Lite with a Longse LS-RT2412.

Decided to use a Cross Over cable and lo and behold, the cAP Lite powers up.

There got to be some issues on how these switches detect the device, otherwise I don't see why a cross over cable works and a straight one does not.

Indeed support for 802.3af/at seems like a small magic in Routerboard devices. Even official compatibility matrix shows need for crossed cables with some RB devices, including cAP lite.
The table actually suggests (based on columns 2 and 3) that some RB devices are picky about polarity (and not all of them prefer same polarity) while some devices aren't.

PoE article on wikipedia offers some explanation about need for cross-over cables (in the Powering devices section). Seems like PD (power sink) is responsible to implement kind of a "auto MDI/MDI-X" operation for PoE, PSE (power source) will always output same polarity.

My guess is the PD has the resistance installed on another pair from where the PSE sends the signal, thus not detecting PoE on the device and not powering it up. By doing a crossover cable, the signal gets response and powers it up.

From the wikipedia article:

A PD indicates that it is standards-compliant by placing a 25 kΩ resistor between the powered pairs.

Resistors, being symmetrical passive elements, don't care about cross-over cables ... power polarity, however, does.