This is an electronic viewing window, into an area that you not at.
Closed Circuit Television.
the closed circuit my include a means of communicating over a distance, for viewing of a secured group of people, my be in a remote monitoring station (third party), or by yourself these days on you laptop or even iPod/pda/phone/blackberry.
Sorry this installation was not one of my best, but it was a quick install on a house so the owner could see what his dog was doing in the back garden.
The junction boxes would norramly be in a water proof box, but saying that this has worked in all weathers for about two years now. !!
This was the little two camera controller I user for the dog watch system.