Since cards plug into a PC PCI, ISA, PCIe or another slot type this could be useful for a POE system.
If it's some USB 3.0 to Ethernet DONGLE (adapter) then this would be useful for a laptop that had no Ethernet.
As to how it works, any treatise on electronics would not fit here.
Bob
I am a computer newbie so I am not good at computer. I have many questions about it. Recently I saw a ethernet network card. One side of it is USB3.0 port. Another size is RJ45 port. I am interested in it. I want to know its function. Does anyone of you can give an easy to understand answer about how it works?

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