Such an App would be specific to a hardware device. There is no generic app that lets you use just any hardware to make a LAN connection.
Typically all Android devices use either wireless 802.11x or Bluetooth to make a co0nnection to a network. Direct hardware connection is rare, I think.
But i don't know everything.
Google this:
LAN to Smartphone adapter at Walmart
It has been awhile since I visited Walmart. Now they have everything.
