, evildictait​or wrote

WindowsRT does not ship with a wired Ethernet port, and hence they can make more space on your device for pictures of lolcats by not shipping the drivers for the devices that will never be on a WindowsRT device.

If you plug in a USB Ethernet device, you will have to install the drivers from the CD or from Windows Update.

http://winsupersite.com/windows-rt/surface-rt-users-no-ethernet-you

no existing Ethernet adapters work on Surface RT.

http://www.microsoft.com/surface/en-us/support/hardware-and-drivers/usb-to-ethernet-adapter

Surface RT: Surface RT doesn't support use of a USB Ethernet adapter.