Thanks for posting your question here about charging your Nexus 7 and using a USB Ethernet adapter at the same time, I’ll be happy to help.
The short answer is no, our 10 port hub won’t be able to simultaneously power the upstream device and act as hub for the E100 USB to Ethernet adapter. Unfortunately I’m not aware of any devices that do provide this functionality.
Based on some quick searches, it looks like the Nexus 7 should be able to utilize the hub however so I would expect you to be able to use the Ethernet adapter through your hub.
Here’s some more background on this:
USB operates in either Host or Device mode. When you use the On The Go cable to connect the E100 Ethernet adapter to your Nexus 7, the Nexus 7 is operating in host mode. The operating system then needs appropriate drivers for each device that is connected. It does sound like the Nexus 7 has both USB Hub and USB Ethernet drivers based on other peoples reports. One thing to consider is that the Plugable 10 Port USB Hub actually has two host controllers inside. Your Nexus 7 may not be able to handle cascaded controllers so if you do want to use the hub (even though it won’t charge) try connecting into one of the ports on the side with the flip up ports. These and the two ports across from the power connection are on the top level hub.
For charging the Nexus 7, it’s in device mode.
Powered USB hubs generally don’t allow the 5V circuit to return to the host device by design. In some cases power from a self powered hub does return to the computer but it can cause problems for the machine.
What this means is that the 5V lines leaving the mini B port of the hub do not carry any current. It could be possible to find a specialty cable that has two ‘A’ connectors that would bridge the power to the upstream Host device. These do exist but are rare. Note that these are not the general Y cable that provides extra power to the device.
Then, even if the voltage was there, the Nexus’ charging intelligence would have to be active while it’s in Host mode, and we can’t say for sure if that’s the case or not.
I hope this helps in understanding this complicated topic. Hopefully things will get more clear in the future but at the moment there just isn’t much support for this functionality.
Thanks for posting! Let me know if there’s anything else I can do to help.