The mobile phone is connected to the base station through radio within the frequency range, and the data, sound, text, image and other electrical signals to be transmitted are modulated on radio waves and transmitted to the other party. 5G mobile phone jammers emit electromagnetic interference signals whose carrier frequency is the same as the carrier frequency of the base station signal. Therefore, garbled interference will be formed when the mobile phone receives the signal. The mobile phone cannot detect which is the normal data sent by the base station and which is the interference signal, effectively blocking the normal operation of the mobile phone signal.

Signal shielding principle: When the signal jammer is working, it will emit interference signals that interfere with the base station channel frequency band. Interference signals increase the bit error rate of the channel, reduce the signal-to-noise ratio of the channel, prevent the mobile phone from properly decoding the information sent by the base station, and prevent the mobile phone from establishing a normal connection with the base station. When the mobile phone cannot determine the service area after multiple attempts, the mobile phone will display No Signal, Search Network, and Not in the Service Area. It's like starting the engine of a sports car and then you're talking on the phone next to it. The local noise is strong enough to prevent devices from connecting properly, effectively blocking the normal operation of mobile phone signals.

Many customers who inquire about 5G jammers will ask to block some mobile phones or open communication to some mobile phones. This kind of functional device is called a black and white list function. So do the jammers you usually use have a black and white list function?

Generally speaking, a single set of signal shielding equipment does not have the black and white list function. This is because the working principle of common shielding equipment is relatively simple. Most of the interference signals (white noise) are amplified, then gradually amplified by the power, and emitted through the antenna. When a mobile phone user enters the coverage area of a shielded signal, the signal shielding for different mobile phone numbers is not targeted and has no distinguishing function. Therefore, the shielding effect for different mobile phone numbers is to block the signals indiscriminately, and this kind of indiscriminate The only difference is the mobile phone number, which does not distinguish the operator to which the mobile phone belongs, nor which network standard such as 2G, 3G, 4G, etc., or the 5G the mobile phone runs on.

The black and white list function is usually a function of signal smart hosts, mobile phone signal detectors, etc., which can effectively protect the mobile phone detection communications of whitelist personnel, and can effectively block other mobile phone communications within the coverage area. This type of product works with a mobile phone signal jammer to effectively control mobile phone signals in the area. At present, 5G mobile phone jammers, signal detectors and other control equipment have been widely used in special places such as detention centers, drug rehabilitation centers, and non-controlled centers.