Why use a mobile phone signal jammer in the exam room?

Why is there always no signal on my mobile phone in the exam room, is there a jammer installed?

Topsignaljammer  2022.3

In today's information age, with the development of science and technology, communication devices such as mobile phones have appeared, making people's lives more convenient. After experiencing constant upgrading, the functions of mobile phones have gradually become more and more, such as watching movies, chatting and surfing the Internet. However, there will be some people who will use their mobile phones to cheat in the exam, which breaks the original fairness of the exam and is a very bad behavior. This kind of behavior is also expressly prohibited in the exam. Nowadays, in order to prevent or eliminate this phenomenon in the examination room, the installation of mobile phone signal jammer in the examination room has become the main means.