Blocking noise: the function and use of signal jammers
In some occasions, such as conference rooms, cinemas, libraries and other places where quietness is required, using a cell phone jammer ( https://www.jammermfg.com/cell-phone-jammers.html ) can effectively prevent the ringing or call sounds of mobile phones from interfering with the surrounding environment.
In addition, a WiFi jamming device ( https://www.jammermfg.com/wifi-jammer.html ) is also a common signal jammer that can shield the transmission and reception of wireless network signals.