Start / All Programs / Accessories / Command Prompt
Likely there will be more than one listed, so which? Exclude the ones under a heading that says wireless.
For the wired connector, you will see the text media disconnected, or not, depending on whether there’s a live cable plugged in when you run the command.
Finder / Applications / Utilities / Terminal.app
The third line reads something like
From www.mun.ca, search for wired network connections.