If you always hear the prompt "The user you dialed is temporarily out of service area" when calling your friend's mobile phone, don't think that he must be in the remote signal blind area. Maybe he just turned on GPS jammers that blocked the signal and turned the phone off.

　　With the development of science and technology, smart phones have gradually replaced traditional PCs and penetrated into all aspects of people's entertainment life. From a single call function in the past, to today's integration of calls, text messages, photos, Internet access, listening to songs, and e-books, mobile phones not only greatly meet people's communication needs, but also meet people's entertainment needs. While promoting communication, it also shortens people's life distance, unintentionally widens people's emotional distance, unifies facial expressions, and dulls spoken language.

　　Information needs are the natural needs of every social person. People living in society have group needs, isolation and lack of information are non-social characteristics. Information can remove people's uncertainty. There is a "use and fulfillment" theory in communication. "Use and Satisfaction" studies view audience members as individuals with specific "needs" and their media engagement activities as the process of "using" media based on the motivation of specific needs, so that those needs are "satisfied". Newspapers, radio and television media report a large number of current affairs news every day, so that people can understand what is happening in the world and eliminate the uncertainty of people's information. Mobile phone information carriers are more convenient, direct and fast than newspapers, radio and television information carriers.

　　The functions of mobile phones are getting richer and richer. From the initial calls, sending and receiving text messages, to later music, video playback and recording, and Internet access, it has greatly affected people's lives. A double-edged sword". It is necessary to correctly understand the various functions of the mobile phone and play its positive role. There are still many illegal photos, illegal videos, etc., which will violate the privacy of others.

　　Mobile phones have become an extremely important part of people's lives. Its function has changed from answering calls and texting to reading Weibo, playing games and even shopping. People are becoming more and more dependent on their mobile phones. "Human-machine communication" gradually replaced "interpersonal communication" leading to neglect of family affection.

　　The mobile signal jammer can be turned on after booting, which can not only block the WiFi signal, but also complete the synchronization effect of blocking the mobile phone signal. The signal bar on the phone will show zero bars. In this state, the phone can browse web pages, videos and play games online without Internet access.