Min are a little more flexible that that. The link in my siggy will tell you more. It can be triggered by low battery, illegal movement, entry or exit to a restricted area: i can be hooked to a number of sensors which will send the alert when they are triggered, and it can activate switches that will do pretty much anything you like. Some people configure them to disable the ignition and/or tun off their engine, a couple of trucker I know use it to turn on the heater in the cab before thy get to work!
One organization has had it rigged to illuminate a flat flashing light on the ruck roof... making it easily spotted from the air.
It is really a case of what you what from it, rather than what it is capable of.
We can chat on the phone i it would help?