the wire that goes to my door is to lock/unlock the door. last time i checked, when my door was locked with the alarm system set, i tried openning it, and nothign went off. obviously i have a cheap system. i dont' like carrying around a huge remote, so i just don't use the alarm for right now.
so i think the wire is for locking and unlocking only.
alarm goes off when i open the door with the system on.