Unusual device in hall?

Question

I moved back into my dorm for college and I just noticed an unusual device in the hall that's never been there before. It kinda makes a soft fuzzy sound kinda like when a speaker or headphones are on but no music or noise is playing. I'm pretty sure it's not a speaker and some type of surveillance device because I heard from someone that it's to make sure people arn't breaking parietals (i'm at a catholic institution...)

I've attached some pictures here. On the Side it says "N4-A"

http://img169.imageshack.us/img169/1099/photo102mm8.jpg

http://img169.imageshack.us/img169/3651/photo103rs0.jpg

Answer 1

I can honestly say I have no idea and I have seen quite a few alarm systems over the years. It may be just as you suspect a Noise/vibration sensor, but again not like any I have ever seen. They are normally a square with a hole in the middle that takes in the sound and measures the distance and or decibels of vibration in the air. It would seem if they were worried about you breaking parietals a standard motion detector would accomplish the same goal if no one is supposed to be out in the halls after a certain hour. It could just be a speaker; alto of schools upgraded their warning systems after what happened at Va. Tech and a lot of speakers do emit a buzzing sound when they are running. Of course you could just go out after hours and see if the thing goes off, then you would know if it was an alarm.  

Answer 2

Questioning this device is a thought crime.  You are ordered to report yourself to the ministry of the truth for debriefing and reprogramming.

Answer 3

It sounds like you might have a "sound masking" speaker there or maybe just a standard PA system speaker.  If the speaker is constantly emitting a "shhhhh" sound, it could very well be a sound masking system.  They are used in many public spaces now to cut down on the ability for you to hear other people talking.

If the picture was a little more close up, maybe I could help more.

http://en.wikipedia.org/wiki/Sound_maski...

You might ask a building maintenance person at the school.  They probably will know right away what it is.