I know that you can install pretty simple alarm devices, with either access to land line or cell communications, that will dial out when an alarm is tripped. Doesn't cost much.
Instead of going to a monitoring station, you program the system to dial your number with a message: Door Opened, Door Closed, A55hat of STBX opened door, whatever.
Not that I am suggesting this, but this is defeatable, since it is relying on your home phone for notification. It is as simple as disconnecting the phone system where it enters the house (or outside of the house), opening the door. Find what you were looking for. Find the security system, reset the system and immediately leave the room and close the door before it completely reboots - it will not notice the door for the first 15secs or so, enough time to get out of there. Then reconnect phone lines.
So: Moral of this story: If you're gonna have a home security system, best bet is to hook it to a wireless phone card. Makes it more difficult to defeat.
Audaces fortuna iuvat.
The meaning of life is Happiness. What makes you happy? - Dalai Lama
For a more peaceful life, live the serenity prayer.