Mobile phone jammer, also known as "mobile phone signal jammer", "GSM jammer", "venue purifier" or "mobile phone signal smart jammer", is a radio transmitting device that blocks mobile phone communication. The reporter learned that the country’s most authoritative document on mobile phone jammers is Document  No. 439 issued by the Non-Regulatory Bureau of the Ministry of Information Industry in 2001. The document stated: "Recently, some units in the society have developed and produced radio jamming equipment, and used them in some departments and units... This kind of equipment disrupts the order of radio waves and seriously violates the legal freedom of communication of mobile phone users. It must be given according to law. Stop. According to the regulations of China's radio management, radio interference shall not be performed on radio stations (including mobile phones) set up in accordance with the law (except as otherwise provided by laws and regulations)... Develop, produce and use radio interference equipment without going through legal procedures They are all illegal acts." "Radio management agencies at all levels...should start from the source of development and production of radio jamming equipment...Users who use radio jamming equipment without authorization should be punished for setting up stations without authorization and interfering with radio services.