Signal jammer is a popular product, especially in some colleges and universities, because each examination room near the examination center will be equipped with a signal shielding device and a handheld metal detector. The use of signal shielding equipment can effectively solve the problem of cheating in the examination room and create a good examination room environment for candidates. Therefore, it is widely concerned by universities.

Generally, signal jammers are mostly used in classrooms, with built-in blocking jamming signals, which can shield all 2g 3g 4G 5g signals, 2.4G WiFi signals and Bluetooth signals under the three operators of China Mobile, China Unicom and Telecom. The actual effective shielding distance is inversely proportional to the signal strength of mobile phones on the site. The weaker the communication strength, the larger the shielding range. The principle of the signal jammer is to interfere with the frequencies sent by the mobile phone receiving the base station and the wireless router through its own frequencies, so as to achieve the purpose of shielding them. Therefore, as long as the shielding equipment is turned on in the room, the mobile phone cannot receive and make calls, receive and send text messages and surf the Internet. At the same time, without affecting the use of other electronic instruments, it ensures the silence and confidentiality of the on-site environment. Once the mobile phone leaves the partition area, it can be restored to normal use.