When the communication technology developed to the 2G era, signal jammers were able to function perfectly. At that time, most operators used the same frequency band, and the frequency was relatively fixed, so it was relatively easy to interfere with it.
With the rapid development of communication technology. 3G and 4G communications were quickly applied to actual scenarios. At this time, the signal jammer encountered a dilemma, that is, the signal interference originally designed for 2G, because of the frequency, it cannot cover 3G and 4G signals. This also renders the shield ineffective.
In this case, the development of communication technology has begun to force the simultaneous development of shielding technology. In order to be able to interfere with 3G and 4G signals, the jammer quickly evolved a special interference function for 3G and 4G frequency bands. Then there is a problem that 2G, 3G and 4G all need to be shielded, so how about it? How about shielding these three frequency bands at the same time and space?
The answer is simple. The interference bands corresponding to the three signals are repeatedly played in a loop to cover the three bands at once, and the interval of this loop is so small that the phone has no chance to speak and can only sit down.
Based on this principle, the signal jammer was first developed and everyone was happy. The prison only needs to be equipped with a few jammers that can emit such noise to shield the mobile phone communication within the entire prison. And with the need to shield the signal more and more scenes. Signal jammers that were originally designed to be used in prisons have gradually entered normal commercial scenarios, such as important meetings and exams.