Why did the mobile phone suddenly become a 2G network?

1, the mobile phone suddenly becomes 2G. It is possible that the signal is blocked in closed spaces such as elevators and high-speed trains, which will lead to only 2G signals, so it will suddenly become 2G. Generally, the signal will return to normal after getting out of the elevator or high-speed rail.

2. During the call, the mobile phone system may suddenly switch the network from 4G to 2G. Because the mobile phone makes voice calls through 2G signals, it will suddenly switch to 2G signals when answering the phone.

3. The mobile phone is suddenly switched to 2G, which may be that criminals interfere with 3G and 4G signals, forcing users to "reduce the dimension" to 2G network status. When the mobile phone is changed to 2G, there will be many loopholes in the mobile phone, because the most obvious loophole in the 2G system is that the legitimacy of the base station has not been verified, so the criminals have an opportunity. Therefore, we must pay attention to this situation. We can turn off the cellular data of the mobile phone, or turn it off, or change it to flight mode, so as not to be afraid of being used by criminals.