In some security areas, it is necessary to block incoming and outgoing communications. The main purpose is to prevent unauthorized devices from illegally communicating with mobile phones, cameras, miniature cameras, microphones, and data transmission. Although these devices can block more conventional frequencies, they cannot always block the entire telecommunications spectrum. The safest method known is the Faraday cage, which is completely covered by a metal cage (place) to prevent external and internal communication. This is neither feasible nor practical because it will be a completely isolated place to prevent communication. These mobile cell phone jammer are placed in most official vehicles to avoid serious security risks, such as terrorist attacks or government opponents. They usually have a medium range, but obviously do not have all frequencies, but their purpose is to provide bubbles with sufficient range to avoid direct impact from bombs. It is also used to prevent safety risks, such as vehicle location. For dignitaries or VIPs, these devices are used with ballistic protection to prepare the vehicle for any situation.
The mobile phone jammer device replaces the mobile phone by transmitting the signal at the same frequency and high enough power, so that the two signals collide and cancel each other. Mobile phones are designed to increase power when encountering low-level interference. Therefore, the jammer must recognize and match the increase in phone power. Cell phones are full-duplex devices, which means they use two different frequencies, one for talking and the other for simultaneous listening. Some cell phone jammers only block one of the frequencies used by the phone, which effectively blocks both frequencies. The phone is tricked into thinking that it has no service because it can only receive one of these frequencies. Interfering mobile phones have GPS jammers instead of any other types of expensive radio communications. The working principle of a mobile phone is to communicate with its service network through a mobile phone tower or base station. Cell phone towers divide the city into small areas or communities. When the mobile phone user is driving on the street, the signal will be transmitted sequentially.