In order to explain how cellular jammers work, we need to first understand how mobile phones work.
The cellular phone communicates with cellular base stations by transmitting signals with ID codes at regular intervals.
This notifies cellular network that our cellular phone is “ON” and is in coverage area.
Now imagine that this communication is interfered by a white noise signal transmitted by the cellular jammer. The communication between the base station and the cellular phone is cut off and the cellular phone is totally blocked, which makes the receiver in the cellular phone “think” that the cellular phone is not in coverage area.
After 20-60 seconds the mobile phone display will show “NO SERVICE” or “Searching for network”.
From this moment the cellular phone will not be able to receive or make calls.
The cellular phone will be ready for use again after switching off the cellular jammer.