The mobile phone jammer can connect the base station and the mobile phone through radio waves within the effective frequency range, and use a certain frequency baud rate and modulation method to complete the transmission of data and sound. This is the function of the mobile phone jammer. Communication principle, according to this principle, the mobile phone jammer can scan the low-end frequency from low to high to high-end frequency at a certain speed when working.At this scanning speed, garbled interference can be formed when the mobile phone receives the signal. Therefore, the mobile phone cannot detect the signal sent by the base station when receiving data. This interference prevents the mobile phone from completely establishing a connection with the base station. Relationship, this form of expression is the phenomenon of being unable to search for signals, no service, no signal, etc. In this case, you cannot send messages or make calls. How to avoid the interference of signal jammerMethod 1: Due to the rapid development of wireless networks, it has now developed into 4G networks, and many examination rooms use older models of signal jammers, which can only block 2G networks such as PHS, China Mobile, and China Unicom. 3G and even the current 4G network are helpless. The solution is to use a 3G or 4G card.Method 2: Band cracking method. Because the working principle of the school's jammer is to block the mobile phone by interfering with the mobile phone signal in the specified band, you can prevent it from being blocked by modifying the mobile phone's receiving and transmitting frequency. The jammer only blocks the 900-1800MHZ mobile phone signal, while the mobile phone's receiving and transmitting frequency The frequency is 850-1900MHZ, which is much larger than the shielding range of the jammer, so as long as the mobile phone's receiving and transmitting frequency is adjusted to the maximum in the mobile phone settings, the mobile phone signal can be received normally.Method three: WIFI cracking method. This method has relatively high environmental requirements, provided that there must be an available wireless network around. Some mobile phone jammers cannot block WIFI signals and can communicate with the outside world.Method 4: Bluetooth cracking method. It is suitable for short-distance communication in a shielded area. Some jammers may ignore the transmission function of Bluetooth and do not shield it, so we only need to install Bluetooth messaging software on the mobile phone to communicate normally in a small range.