How the heck does the alarm system work?
 

Hi. I've a 1999 Eclipse GS manual trans. It has some kind of alarm or anti-theft thing on it. Was that a factory option? And if so, how does it work? It has gone off twice, but I don't know what I did to arm it. Those two times (I think) I've locked my car from inside, gotten out, and then to get back in I unlock it as you would by putting the key in the door and turning. So does anyone know how to arm/disarm it? Thanks in advance.

Godspeed.
Ethan.