Mobile phone signal jammers have become standard equipment in examination halls, not just for high school and college entrance exams, but also for graduate exams, civil service exams, and various professional certification tests. Examination halls equipped with Dazhan Electronics' mobile phone signal jammers see the disruption of various mobile signals (2G, 3G, 4G, 5G), wireless walkie-talkie signals, Bluetooth and WiFi signals.

Let's delve into how mobile phone signal jammers manage to interfere with your phone signals.

We can temporarily compare mobile phones to radios. Radios sometimes experience static or channel confusion, rendering them inaudible – this is due to signal interference. Just as radios can be interfered with, so can mobile phones, either naturally or through certain devices.

Mobile phone signal jammers go by many names: blockers, mobile blockers, signal blockers, mobile signal jammers, mobile signal interrupters, mobile isolators, mobile cutters, mobile communication signal blockers, mobile signal shielding devices, mobile jammers, signal jammers, mobile interrupters, signal interrupters, mobile signal isolators, signal isolators, mobile signal cutters, radio signal blockers.

These devices target the uplink and downlink channels of the mobile system, employing techniques such as frequency multiplication, division, and frequency hopping filtering to analyze the required blocking frequencies. Depending on the jammer's power, a spherical shielding space is customized, automatically forming a shielding magnetic field within a specified range, rendering mobile phones (including PHS, GSM, CDMA) ineffective in this space. When the jammer is operating, it disables the reception and transmission functions of mobile phones within the designated range, preventing calls from being made or received, achieving the purpose of forced disabling.

Principles of radio communication: Within a certain frequency range, mobile phones connect to base stations via wireless electromagnetic waves, transmitting data and voice at a specific baud rate and modulation method.

The working principle of mobile phone signal jammers involves scanning at a certain speed from the lower end of the forward channel frequency to the upper end. This scanning speed creates garbled interference in the phone's received message signals, preventing the phone from detecting the normal data sent from the base station, thus stopping the phone from establishing a connection with the base station. The phone displays as searching for a network, no signal, no service system, etc.

Since we know that wireless communication relies on electromagnetic waves,

the functional characteristics of electromagnetic waves are determined by their frequency.

Different communication systems use different frequencies, coexisting without interference. The basic principle of mobile phone interference devices is to emit radio signals identical to those of mobile phones. Due to the same frequency, the phone cannot distinguish between regular base station signals and the "interference," achieving the effect of "jamming." All that's needed is a machine with the same frequency as the phone; when the base station attempts to connect to the phone, it emits a lot of "noise," making it impossible for the phone to identify the signal, leading to refusal of communication.

Initially, jammers blocked only a single set of frequencies, such as 2G, whereas sophisticated jammers can simultaneously block several types of networks, including 2G, 3G, 4G, and 5G. How is this multi-network jamming achieved?

It's actually simple. By cyclically repeating interference bands corresponding to these three signals, simultaneously covering all three interference bands, the cycle interval is so small that the phone has no opportunity to communicate, sitting quietly like a brick.

Having covered 2G, 3G, 4G, and 5G, what about Bluetooth and WiFi? No problem, they can be handled just as easily.

Jammers have evolved once again, incorporating Bluetooth and WiFi frequency bands into their scanning range, thus completely covering the common communication methods in society.

Many people don't understand the differences between Bluetooth, WiFi, and mobile data, assuming they are all wireless communication technologies. In reality, the main difference lies in their frequency bands. In mobile communication technology, 2G mainly operates in the 900-1700 MHz band, 3G in the 1900-2100 MHz band, 4G in the 2300-2500 MHz band, and 5G in the 3400-3600 MHz band. Bluetooth and WiFi operate in the 2.4 GHz band.