Telephone signal jammers mainly use mobile phones in doctor's offices, schools, gas stations, churches, courts, libraries, conference centers (rooms), theaters, hospitals, governments, finances, prisons, public security, military powers, etc. It targets a variety of prohibited locations. It is understood that cell phone jammer on the market can limit mobile phone signals at a distance of 500 million meters from the launch station. The shield radius is adjustable and the coverage area is over 30 square meters. Mobile jammers can only shield mobile phone signals without affecting other electronic devices. Save power. The power is 12W-480W. The jammer scans the forward channel from the low-end frequency to the high-end at a specific speed during operation. This scan speed can cause garbled interference in the message signal received by the mobile phone, and the mobile phone cannot detect normal data transmitted from the base station, so the mobile phone connects with the base station. Cannot be established. Mobile phones appear as a phenomenon of searching the network, no signal on the mobile phone, no service system, and so on.