i'm no computer scientist, but don't i have to request information in order to receive it?
What i mean is, do i have to attach a LED light to my laptop to request the data from the LED in my roof?
Yes and no. One could just receive broadcasted data -- a monitor on the other side of the room really doesn't need to send much info back. For a laptop, one wouldn't necessarily need to request data via an LED, the requests could be made over some other medium, like traditional wifi, with the responses coming from the LED.