A gsm jammer or blocker is a device which deliberately transmits signals on the same radio frequencies as mobile phones, disrupting the communication between the phone and the cell-phone base station, effectively disabling mobile phones within the range of the jammer, preventing them from receiving signals.
In schools. For teachers, gsm networks and smartphones are just tools to distract students' attention. Now, a student can do all that and a 1,000 other things on one screen. How does a teacher of any quality compete with YouTube, Snapchat, Trivia Crack, or even PornHub? So, sometimes schools have to resort to semi-compulsory means of using gsm Blocker.