The Mysterious Car-mounted Frequency Interference Device: A Journey of its Origins and Applications

In this article, we will delve into the origins and applications of the car-mounted frequency interference device, a remarkable tool that has gained significant attention. Initially designed for prison settings, this device was created to ensure information security and privacy within the confines of correctional facilities. However, its utility has expanded beyond prisons, finding relevance in various scenarios where signal interference is required.

Origins in Prison Settings:

The primary purpose of the car-mounted frequency interference device was to isolate communication signals between prisons and the outside world, thereby safeguarding the integrity of information within the prison walls. During the initial stages of its development, the world was still in the era of 2G technology. Although there were three major telecommunications operators in China, all mobile phones operated on the second-generation network communication technology. The communication frequencies used by different manufacturers were relatively similar. The ability of mobile phones to make and receive calls relied heavily on the support of communication base stations. Upon powering on, a mobile phone would automatically connect to the nearest base station, which would then direct the phone’s communication. Therefore, if a prison wished to disrupt communication between inmates and the outside world, a simple solution was required.

Disrupting Communication:

The answer to disrupting communication was surprisingly straightforward – a machine emitting noise at the same frequency as mobile phones. When a base station attempted to connect with a phone, it would encounter a distorted and unrecognizable signal due to the interference generated by the car-mounted frequency interference device. Consequently, the base station would reject any communication attempts from the phone. This principle formed the basis for the development of the car-mounted frequency interference device, which proved to be a highly effective tool for prisons. By equipping a few of these devices, prisons could disrupt mobile phone communication within their premises.

Expanding Applications:

As the need for signal interference grew, the applications of the car-mounted frequency interference device expanded beyond prison settings. Various scenarios, such as examination halls, military operations, and confidential meetings, required the prevention of unauthorized communication. The device’s ability to disrupt signals within a specific range made it an invaluable tool in maintaining security and privacy. With advancements in technology, the car-mounted frequency interference device has evolved to adapt to different frequency bands and interference levels, ensuring its effectiveness in diverse environments.


The car-mounted frequency interference device, initially designed for prison settings, has proven to be a versatile tool in maintaining information security and privacy. Its ability to disrupt communication signals within a specific range has found relevance in various scenarios beyond prisons. As technology continues to advance, it is likely that the car-mounted frequency interference device will further evolve to meet the ever-changing demands of signal interference.