Could be a lot of things, maybe a tone detector driven from the speaker to trip the relay (white box), why do you care? Hero, how does this promote terrorist activities? The circuits required to modify a cell phone and a pager into an IED trigger a smart high school student could figure out, showing a single blurry image of an ugly hack on a phone doesn't promote anything except perhaps the fact that the person that made the device made it wrong.
I'm not even sure why you would suggest it was a micro controller, PIC or otherwise.