The wall jack in my apartment.

I know this is an stupid question but I can't seem to find the answer.

There are LAN outlets on the wall of my apartment and I don't know what they do. I live in a big facility so I don't know if I can share my internet connection by plugging my router in one and my PC in another. Or are they suppose to provide some service that comes from a main source in the building?

I'm in a foreign country and it is not possible for me to ask this from anyone in charge as we don't speak the same language. So I thought I ask you guys before going out and buying LAN cables.

Thanks