A Ring Tone Meant to Fall on Deaf Ears - New York Times

A Ring Tone Meant to Fall on Deaf Ears - New York Times:

"At Roslyn, as at most schools, cellphones must be turned off during class. But one morning last week, a high-pitched ring tone went off that set teeth on edge for anyone who could hear it. To the students' surprise, that group included their teacher.
'Whose cellphone is that?' Miss Musorofiti demanded, demonstrating that at 28, her ears had not lost their sensitivity to strangely annoying, high-pitched, though virtually inaudible tones.
'You can hear that?' one of them asked.
'Adults are not supposed to be able to hear that,' said another, according to the teacher's account.
She had indeed heard that, Miss Musorofiti said, adding, 'Now turn it off.'
The cellphone ring tone that she heard was the offshoot of an invention called the Mosquito, developed last year by a Welsh security company to annoy teenagers and gratify adults, not the other way around.
It was marketed as an ultrasonic teenager repellent, an ear-splitting 17-kilohertz buzzer designed to help shopkeepers disperse young people loitering in front of their stores while leaving adults unaffected." Article Quote