If I'm getting this right...you put one on both sides of a wall separating two rooms. You can have your room with the mixing and tracking equipment, and you run those cables into the wall. The other room has the musicians performing, and those cables run to the mics that are recording them. It just allows for better separation, and like somebody on here said, you don't have to try to close a door over 20 cables.
so if i have mic pre in the tracking room and plug a cable in a slot, i plug the other mic cable in the matching slot in the other room, right...