This is pretty neat. I can't hear it, but Arlo can.
A Ring Tone Meant to Fall on Deaf Ears
"When I heard about it I didn't believe it at first," said Donna Lewis, a technology teacher at the Trinity School in Manhattan. "But one of the kids gave me a copy, and I sent it to a colleague. She played it for her first graders. All of them could hear it, and neither she nor I could."
The technology, which relies on the fact that most adults gradually lose the ability to hear high-pitched sounds, was developed in Britain but has only recently spread to America — by Internet, of course.
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.