Secret cellphone ring tone?

A high-pitched alarm which cannot be heard by adults is being used by schoolchildren to create cell phone ringtones so they can get away with using phones in class.

Techno-savvy pupils have adapted the Mosquito alarm, used to drive teenage gangs away from shopping centres.

The alarm, which has been praised by police, is highly effective because its ultra-high sound can be heard only by youths but not by most people over 20.

Schoolchildren have recorded the sound, which they named Teen Buzz, and spread it from phone to phone via text messages. Now they can receive calls and texts during lessons without teachers having the faintest idea what is going on.

A secondary school teacher in Cardiff said: 'All the kids were laughing about something, but I didn't know what. They know phones must be turned off during school. They could all hear somebody's phone ringing but I couldn't hear a thing.

The Mosquito technology is said to play on a medical phenomenon called presbycusis, or age-related hearing loss. It is thought to begin at 20 and first affect the highest frequencies – 18 to 20kHz. Click here to download the ringtone, or article here.

So after downloading and listening to this ringtone… I gotta admit it’s pretty cool that the majority of younger people can only hear this.