The law explicitly prohibits the use of devices to actively block mobile phone signals, but there is no rule prohibiting mobile phone passive shielding. For example, this means using wallpaper or building materials with embedded metal pieces to prevent cell phone signals from entering the room or out of the room. Some buildings are designed to accidentally block radio signals due to thick concrete walls and steel frameworks.
I agree with installing cell phone blocker in prisons. "Like other Attorney Generals such as Christiane Taubila, new seal hunter François Bayle responded to the phenomenon of mobile phones in BFMTV and RMC prisons on Tuesday. Photos posted by social network bosses, Pool I smoked a picture taken by a prisoner in his cell, or a marijuana ... Authorities managed to curb this practice, but the problem has been going on for years.
This indoor location tracking application can only be used for grocery sales, logistics efficiency, mobile games, or large shopping centers, international airport terminals, and other large buildings. It is possible to track the internal location of the device, but this is almost impossible. IndoorAtlas conducted several experiments in a tunnel less than 1400 meters underground at a zinc copper mine in central Finland. There, the system can identify itself using mineral deposits and many other anomalies that interfere with the Earth's magnetic field.