"Listen in" Microphones

[broconne]

I am in the process of getting ready to put an offer on a pre-sale semi-custom house we hope to build. Getting ready to meet with the LV contractor today, and while reviewing wiring your house 101 (for about the 10th time it seems - GREAT document), I came across this tip which I don't fully understand:

"Install shielded microphone cable to each keypad location to support "listen in" microphones.

What exactly does that do for me? Why would I want to listen in to the keypad location near my doors?

 

[WayneW]

Depending upon your system, that allows you or your alarm monitoring company to listen to your house. Some governments require some form of alarm verification before dispatching or to determine the priority of the dispatch. I guess the theory is that if you hear normal conversation, then it may be a false alarm or if you hear two thieves talking, you know it is real. I don't know how to interpret dead silence. Some of the listen-ins are two way devices so that gives you a way to talk to someone who "has fallen and cannot get up" to a phone but was able to summon medical help with their pendant trigger. Here are some pros/cons of putting the microphones in the ceiling (better coverage, but visible) versus in the keypads (totally hidden).