The Signal Jammer has become the "standard" product of various examination halls. In order to ensure the fairness and justice of the examination, these signal interference products will be used to block the wireless communication signal and isolate the cheating behavior of electronic products.

These signal interference products are aimed at the uplink and downlink channels of mobile communication, and use frequency interference and other technologies to analyze the required interference frequency according to the actual environment. A certain interference space is formed according to the power of the signal jammer, and an interference magnetic field will be formed within the working range (the larger the power is, the larger the range is), which can make the wireless communication equipment within the specified range invalid in transmitting and receiving signals, and can not transmit or receive signals to the outside world, so as to achieve the purpose of forcibly disabling signals and make the mobile phone unable to access the Internet.

At present, there are many suppliers of mobile phone signal interference, and their products are also diverse. Compared with the signal jammer, power and frequency are the two major factors that determine the product. The size of power determines the place of use, and different frequencies interfere with different frequency bands. According to the on-site use environment and scope, professional manufacturers can be found to select suitable products to avoid poor interference effect and failure to completely block the wireless signal.