Apparently they are in wide use in Chinese and Indian schools. http://pcworld.about.com/od/wirelessphonesvoip/Should-Cell-Phone-Jamming-be-L.htm http://pcworld

Apparently they are in wide use in Chinese and Indian schools. http://pcworld.about.com/od/wirelessphonesvoip/Should-Cell-Phone-Jamming-be-L.htm http://pcworld.about.com/od/wirelessphonesvoip/Should-Cell-P...