 where you would inject the FM signal into the cable. You would bury the cable in the ceiling of the building. And at least according to the documentation I got from them, you measured the part 15 field strength at the exterior of the building at three feet away from the exterior wall, which is what I did for our project. And it worked fairly well considering the budget constraint I was in. So you're in essence wiring up the school building with a cable that acts as a radio antenna.