Even Worse Than That Stupid Frog

Yahoo! news reports on a high frequency ringtone that is inaudible to most adults. It's being used by teenagers to receive messages in classrooms that ban cellphones.

I can hear it, so my students better not get any ideas. Although, I'm thinking that the adult would be the least of a student's worries. The tone is so annoying that the other students might have a bone to pick if it's used repeatedly during class.