Its remarkable how technology can be used in totally two opposite ways, take one of the most popular ringtone of today.

My friend baught a new cell phone and he wanted to try a new ringtone, so we searched net and came to know about Teen Buzz or Mosquito ringtone which can only be heard by people less then 20 year of age. Initially I didn't believe this so I did some search on the topic and found some amazing facts about this invention.

The story goes back to 2005, when Howard Stapleton, a British inventor, came up with a security device designed to keep teenagers away from the shops but leaves most over twenty years of age unaffected.

When a group of teens learned of this technology they decided to use it for their own use: They created a cell phone ringtone called "Teen Buzz," which has caught on like wildfire, first in the UK, and quickly emigrating to the US.

In settings where cellphone use is forbidden like in schools it is perfect for signaling the arrival of a text message without being detected by an teachers.

The principle is based on Presbycusis, a normal loss of acute hearing that occurs with advancing age. Teen Buzz was developed using the same technology, but as a constant 14.4khz high frequency ringtone.

While most human communication takes place in a frequency range between 200 and 8,000 hertz, most adults' ability to hear frequencies higher than that begins to deteriorate in early middle age.

"It's the most common sensory abnormality in the world," said Dr. Rick A. Friedman, an ear surgeon and research scientist at the House Ear Institute in Los Angeles.

The company even released a free sample for everyone to try and see (or should I say hear) for themselves whether they can hear the ringtone before actually paying for it.