This may be a YART, but I got too many hits on the word "alarm" to figure that out. My Turkish friend and I were talking the other day about smoke detectors...

Why does a fire alarm "go off", meaning that it begins to sing? And when it stops singing, what do you use to indicate that? It doesn't "go off"; I would probably say "It stopped". Does this have something to do with the way alarms originally worked? We also say "I set off the fire alarm". (Or the burglar alarm.) Why, oh why?

Are there other situations where a "backward" verb is used like this?