Lets play name that part!
 

ok i was recently doing a little detailing around my car and i happen to lift up the passenger floor mat to find a compartment containg these devices. i think one is the radio/alarm which was unplugged, so i plugged it back in and her a ticking noise....like a bomb ready to detonate, panicked, i unplugged it again. i then waited for about 5 mins and plugged it back in and the same thing happened, then i noticed that my lights were flashing, cool it works! i left it plugged in and i think i started the car or did something it it cut off. there was no horn involved, just flashing lights. my question is, how do i activate it or arm it again. i locked the doors with the key and down windows rolled donw and tried opening the door and nothing. i would also like to know wha the other box is for with the black plug going into it. i see a red plug as well, but i know what that is i think and i will not touch that one. and finally if you look at the engine compartment pics, you can see several holes like something was attached to the engine block....is there something that was supposed to be there? its right below the first spark plug boot at the front of the engine block. i also found a modem underneath the back seat, i think its from a phone as there is a phone line connected to it and i also noticed that on the driver side there appears to be a small microphone protruding from where the ceiling hand rail is. i didnt get pictures of these, but if anyone would like to see exactly what im talking about i can provide you with pics.

I'd assume it was unplugged for a reason.....when those security systems go haywire....they will go off at random.

Those holes in the block are likely for the smog pump mounting bracket. No smog pump = open holes If your car is a '90 or later, then someone removed the smog pump (cool), if earlier than '90, they didn't have one yet.

But I had my smog pump just replaced last year. And how can I activate my alarm again? I plugged it in but I don't know how to arm it

All you have to do is lock the door. If you want a quick and dirty test to see if the alarm works pull your hood release but don't lift up the hood. Then, lock your car and push the hood down shut. Your car should honk and flash its lights.