How to prevent sudden ringing?

When we are in a large meeting, the phone rings every five minutes, which is really annoying. We can use a wifi jammer to block the phone signal and mute the phone. These devices were only discovered a few months ago, until the people in the meeting complained that their phones were not working properly.

In Mexico, prison staff tried to prevent criminals from communicating with their associates and planned to use mobile phones to communicate with the outside world in prison. They purchased signal stoppers, completely avoiding potentially dangerous activities.