Schools use jammer to cheat to ban the use of mobile phones examination is very normal things, prison for security and management, also can use powerful jammer device, banned prisoners, through contact with the outside world communication, reduce the threat to the prison.

Mobile jammers are certainly an advantage if used correctly. Whatever the nature of the environment, the person who continues to talk on the phone can eventually remain silent. Interference transmits high-power signals at the same frequency as a mobile phone to allow the two signals to collide and cancel each other out. This is the basic operating principle of any scrambler. Simpler devices block only one set of frequencies. High-end devices can block all frequencies at the same time. Mobile phones are fully duplex devices, which means they use two different frequencies. One listens and the other speaks. Some basic scramblers can only block one of these frequencies. Advanced scramblers not only interfere with all cell phone signals, but also with many other signals. It also has a unique frequency switch that can be selected on demand.

Most mobile jammers emit at the same radio frequency as nearby phones, sending stronger and more powerful signals to nearby towers. Therefore, when a jammer is activated, its signal immediately blocks all other competing signals, and the nearby tower cannot support anything beyond this powerful and signal making. In other words, use the jammer as a siren or horn to kill conversations nearby. Many countries allow limited mobile interference, especially in the United States, India, Mexico, New Zealand and other areas. Almost all of these countries allow cell phones to be used in prisons. Some of them are allowed to be in schools and even in theaters. Many countries currently prohibit the use of jammers in prisons.

All of this can be done with a cell phone jammer. There is no reason not to confiscate prisons - guards have walking walkie-talkies and are not affected by intruders (they should not even have telephones) so that communications are not uninterrupted. The stuck airspace can be designed and adjusted so as not to affect areas outside the prison. If an emergency is declared and the emergency services must have access to prison, the protocol allows for disabling the scrambler.