What are Cell Phone Jammers and How Does Cell Phone Jamming Works?

Cell phone jammers are devices that create a temporary "dead zone" to all cell phone traffic in their immediate proximity. Jammers are typically used by the police and military to control or disrupt communication during hostage situations and bomb threats.
Traditionally, jammers were large antennas mounted on trailers that had to be pulled behind a truck. They now come in a variety of shapes and sizes including models that are about the size of a cell phone.

How Cell-phone Jammers Work?

Jamming devices overpower the cell phone by transmitting a signal on the same frequency and at a high enough power that the two signals collide and cancel each other out.
Cell phones are designed to add power if they experience low-level interference, so the jammer must recognize and match the power increase from the phone.

To jam a cell phone, all you need is a device that broadcasts on the correct frequencies. Although different cellular systems process signals differently, all cell-phone networks use radio signals that can be interrupted.