How does X1 box connect to the internet

So the X1 box was having 'internet troubles' last night (annoying).   Eventually got things fixed.

But happened to notice the light for the X1 connection on the router wasn't on.   Seems that even though I've connected a hard line from the X1 box to my network, it seemingly connects by Wifi?    I couldn't find anything in settings to change this.    Given a wired connection is always faster and more reliable.

Is there a way to get the X1 box to use the hard line?   (I assume the jack is there for a reason.  )

(And who can you tell what model you have without looking on the bottom - that doesn't seem to be in the menu system either.  My unit is a Pace PX013ANM)