Cell phones may be ringing in your classroom—and you may not be able to hear them.
A new cell phone ringtone that may only be heard by the young has been created from a high-pitched sound originally developed to keep groups of young people from congregating in public places.
The "ultrasonic youth deterrent for shops and homes" was developed in the U.K. by Compound Security Systems in an effort to "disperse gangs of youngsters hanging around the streets," without affecting older generations. Nimble technologists decided the sound would make a perfect ringtone in situations where the young wouldn't want older folks to know that phones were ringing—places like classrooms, for example.
Bootleg versions of the sound as ringtone were becoming so popular that Compound Security Systems (http://www.compoundsecurity.co.uk/) developed Mosquitotone, the official Mosquito ringtone. In the U.S., Mosquitotone is available at http://www.fork.com/, currently only for mp3-compatible phones. Additional formats are expected soon.