Here are two photos of the bathroom waste line. I'm not sure what this huge coupler is. I think that it might be an old dielectric union because the waste line is copper below the union and appears to be galvenized as it rises up. I could be wrong, though.

This is a second floor bathroom on the second story of the house. I haven't removed enough of the wall to know where the waste line terminates higher up.

Pictures below:

Thanks a bunch.