To add on to what ilovetv noted, we have a remote arm/disarm function (via keychain fobs/remotes) for our security system in OH. It allows you to control the arming and disarming of the system, as well as a couple of other functions, from outside the house by using buttons on the remotes. The reason we had this functionality included in the system was so we could have magnetic switches installed on the garage doors - most people opt to not arm their garage doors unless they program in a lengthy delay to allow themselves time to rush into the house upon arrival to disarm the system via a wall-mounted keypad. This way we're able to also protect the contents of the garage without running the risk of tripping the alarm if we didn't make it to the keypad in time (or exiting and not getting the door down quickly enough).
Additionally, we also had water sensors installed in several locations in the house - by the washing machine, the hot water heater, floor drains and sump pit in the basement (in OH!). If any of them detect the presence of water, it'll trip the alarm and call the monitoring center. The system's also programmable for use with X-10 lighting modules - allows you to selectively control interior and/or exterior lighting at your home. (See
www.x10.com) You can also get temperature sensors to monitor inside air temp as well as refrigerator/freezer temps.
The point of all this blathering is to note that, to us, a security/alarm system can be something more than just means to set off an alarm if there's a break in. There is a lot more that can be piggybacked onto a system to expand its functionality.........if that's what floats your boat. We like those features as much as the basic alarm capabilities.
JMHO - - - -
Bill