An attacker can use a cell phone jammer to interrupt the radio connection. Overriding or preventing radio transmission may, for example, interrupt the image of the surveillance camera. These attacks must be considered protection. The jamming transmitter sends a random signal (noise or pulse) with the greatest possible strength at a certain frequency, thereby superimposing the original transmission. If jammers are used exclusively, they are called strategic jammers. These devices are also called jammers, and the process is called noise interference.
There are cell phone jammer of various radio protocols, such as Bluetooth, WiFi, GSM, UMTS, LTE and GPS. Therefore, the specific frequency of the radio protocol is interfered. There are very simple and small devices that can only interfere with radio signals within a limited radius. For example, there is a small adapter for car cigarette lighters that has the function of interfering with GPS signals. A portable device with a battery can reach a maximum distance of 20 meters under optimal conditions, depending on the model. Usually, they interfere with the signal in the room. Powerful fixed equipment can reach a range of 80 meters.
In Germany, the use of jammers is illegal. They are mainly used by investigative agencies and military departments. Some of them are used in prisons to prevent prisoners from making illegal communications. The challenge here is that no outside signals are blocked, such as mobile phone signals for emergency calls. In foreign countries, cell phone jammer are sometimes used in movie theaters and theaters so that the incident will not be interrupted by mobile phone signals. Another use is, for example, to block control signals from drones.
If an attacker uses such a jamming transmitter, the jamming transmitter can be used, for example, to block the radio connection of surveillance cameras or window sensors of alarm systems. Therefore, a broken connection must always be equivalent to an alarm. In addition, interference can be detected by continuously testing the radio connection between two components using a cable connection. If the connection is interrupted, the cell phone jammer is active. Alternatively, but also more difficult to solve technically, you can test the signal level, the strength of the radio signal. If a new strong radiation source is detected here, it may be a source of interference.