It seems that the POE standard is not correct in the specification. 802.3at (https://www.ip-insider.de/was-ist-8023at-poe-a-885551/) should actually deliver 50V. The manufacturer's page for this device only mentions 27V Passive POE. Passive POE from UI is more likely to be 802.11a, 802.11g and 802.11n (https://en.wikipedia.org/wiki/Power_over_Ethernet). But I'm certainly no expert and you probably have internal people who can check this again. But we only bought this product because of the 802.3at and our end device doesn't work. Have a nice day and pay attention to the information!