The principle of the mobile phone signal jammer: scans from the low end frequency of the forward channel to the high end at a certain speed during the working process.

This scanning speed can cause garbled interference in the message signal received by the mobile phone, and the mobile phone cannot detect the normal data sent from the base station, so that the mobile phone cannot establish a connection with the base station.

The mobile phone is manifested as the phenomenon of searching the network, mobile phone no signal, no service system and so on.

You can try the following methods to prevent cell phone signals from being shielded by the shielding device:

1. Turn on the phone, find the "Settings" button, and click to enter.

2. After entering the "Settings" interface, pull down to find the "Dual SIM and Mobile Network" option.

3. Click to open "Dual SIM and Mobile Network", there is a "SIM Information" inside.

4. Click to open the "SIM information" option, you can see the information of the network operator.

5. Follow the prompts and turn off the "automatic selection" button to prevent the mobile phone signal from being blocked by the shielding device.