Nowadyas, with the rapid development of science and technology, more and more innovative products have emerged in market around the world, such as cell phone jammer. Cell phone jammer has been widely used in various places prohibiting the use of cell phone, including schools, gas stations, churches, court, library, conference center, theaters, hospitals, government, finance, prisons, public security and military powerhouse.

It is understood that the current cell phone jammers on the market can limit the cell phone signal beyond the launcher about 500M meters away and its radius is less than 20 meters. The shielding radius is adjustable, it just blocks mobile phone signals, rather than have an impact on other electronic devices. Mobile phone  jammer saves energy, and its power is about 20W - 480W.

Cell phone works in a certain frequency range, the mobile phone connects with the base station via radio waves, cell phone completes the transmission of data and voice at a certain baud rate and modulation scheme. In response to this communication principle, mobile phone jammer scans from high-end to low-end frequency of the channel at a certain speed in the course. The scanning speed can form signal garbled interference after the phone received message, the phone can not detect the normal data sent from the base, so that the phone can not establish a connection with the base station. Phone performs as no signal, no service and no system phenomenon while searching the network.

The frequency of common cell phone jammers in market are 869 ~ 894MHz; 825 ~ 960MHz; 1805 to 1880MHz and 1900 to 1990MHz and CDMA800, GSM900, DCS1800, PCS1900, WCDMA. The range of about 40 meters in diameter can be controlled, use the DC-DC converter to input voltage, and voltage of 5V to output.