The cell phone signal jammer uses the latest Israeli interference technology to generate stable electromagnetic signals, covering mobile communication GSM, CDMA, GPRS, local calls, and PHS frequency bands, so that mobile phones cannot be used in some specific places, thereby solving some problems. Negative effects of cell phone signal in life right now. The common mobile phone signal jammers on the market have the following frequencies: 869~894MHz; 925~960MHz; 1805~1880MHz and 1900~1990MHz, etc. The working frequency bands are CDMA800, GSM900, DCS1800, and PCS1900. It can control the range of about 40 meters in diameter, using DC-DC converter input voltage, 5V output voltage. After the listing of 3G signals, the working frequency bands of the mobile phone signal jammers on the market have also been upgraded from the previous four frequency bands to five frequency bands. On the basis of the previous four frequency bands, there is an additional frequency band of 2100 to 2200. It is used for shielding and interference 3G frequency band. It uses frequency multiplication, frequency division, frequency hopping filtering and other technologies to analyze the required shielding frequency for the uplink and downlink channels of the mobile phone system; customize a spherical shielding space according to the power of the shield, within the specified range Automatically form a shielding magnetic field to make mobile phones (including PHS-China Telecom PHS GSM-China Unicom, China Mobile, CDMA-China Unicom) ineffective in this space. When the jammer is in working state, the function of sending and receiving signals of mobile phones within a specified range can be disabled, and it is impossible to dial out and dial in, so as to achieve the purpose of compulsory disabling.