Signal jammers essentially send interfering signals to communication devices of the same frequency. If the jammer is turned on, the interference part is successful when the area where the mobile phone signal is disabled. Nowadays, with the increasing number of mobile users, some signal interference devices have also emerged to interfere with signals in specific environmental locations. It is sent on the same radio frequency as the mobile phone, interrupting communication between the phone and the tower base station, and refusing to provide radio signals to users within the coverage area of the interfering device.

Nowadays, there are different types of signal jammers in the market. Some devices can only block a single frequency, while others can block multiple types of networks simultaneously. The latter model can automatically switch from different networks to find open signals. Higher end devices can simultaneously block all frequencies, while other devices can tune to specific frequencies. The carrier frequency of the electromagnetic interference signal it emits is the same as the carrier frequency, so the receiver and amplifier are demodulated simultaneously at the receiving terminal. The collision between signals and interfering signals, in simple terms, the signal jammer emits signals over a wide frequency range that are strong enough that nearby devices cannot connect to their intended connection. Therefore, the device cannot make regular connections. By quickly covering a range of frequencies, they can effectively prevent electronic devices from operating normally.