Security Gate + Cell Phone = ??? OK guys, I have a "how does this work" question. I just moved into a new apartment which has a security gate. Now, aside from a few traditional means of opening, it has a rather unusual method, which I cannot figure out how works. My phone number was entered into some database/program. Now, if anyone pulls up to the gate, they call me, at which time I press the "9" button, and the gate opens. Are cell phone calls that easy to monitor that they can simply set up some sort of receiver to "listen in" for that particular button tone? How do they know who the person at the gate is actually talking to?