Mobile phone jammers radiate the same radio frequencies as mobile phones, so they act like jammers. This causes enough interference that the call cannot connect to the phone. Currently, there are two types of cell phone blocker. The first category is usually small devices that prevent signals from being sent from the cell phone tower to each cell phone. The blocking frequency is 800MHz to 1900MHz. Most devices that use this technology can block signals within a radius of 30 feet. Phones in this area do not display any signals.
Now you can close them politely and leave, or you can buy a cell phone jammer and leave them alone.
Unfortunately, they are becoming more and more important because many people (especially prison guards) want to believe that new tech products can solve their problems. A group of prison guards not only filed a petition with the FCC to develop the rules, but also upheld a bill requiring the FCC to allow the use of mobile phones in prisons.
Among the four churches in Monterey, an Israeli paperback-sized paper cell phone jammer is hidden between a Madonna-like painting and a statue of a saint.
Japan allows gps blocker to be installed in public places such as theaters and concert halls, but only if you need to obtain a government-issued license. Last week, the French Minister of Industry approved a decision requesting the establishment of cinemas, concert halls and theaters, provided that emergency calls could be arranged.