how do you disarm home alarm systems?

ADT

Wow, if that doesn't send up red flags!
You put in the right code to turn it off, if that doesn't work you aren't in your house.
Yeah, right....I'm sure you can look this up on the web somewhere, but I wonder what you're going to do about the hungry attack dogs!
Stupid question requires a stupid answer so here goes.... Break a window in the house, when the police show up, they'll happily reset the alarm code for you - no charge of course!
Personally, I think if you want the straight dope about how to get into ADT home alarm systems, you should consult their website, or call one of their field representatives. =) Obviously you have to be pretty fairly mechanically inclined and know a thing or two about wiring and electronics. I would think that if you looked online and did some reading nd checked out some schematics of the unit or devices in question, you might be able to answer your own question. Cheers, and good luck. =D
why do you want to know??!! lol