The Master Side that needs to be plugged to a Computer since it needs the computer CPU and other part to process the traffic, and a Client side that is connected to the peripheral device.
Regular USB to Ethernet adaptor has to plugged into a Computer?s USB and can replace the PCI NIC.
There are few propriety USB adaptors that are built with emulation of the CPU Side? in them (and thus they are always more expensive) and therefore can be plugged into the None computer device it designed for.
As an example there is USB printer server that can turn a USB printer into Ethernet Printer Server.
Otherwise there is NO General USB to Network device.
Besides it does Not matter what is the interface if a Device is Not capable to be handle by Windows Network it want show as a Network device. As an Example sticking USB to Ethernet on a Scanner will turn the scanner into a Network recognizable device.