Cell phone jammers are devices that generate a temporary “dead zone” to all cell phone traffic in their immediate propinquity. Jammers are usually used by the police and military to control or disrupt communication in the work of hostage situations and bomb threats.

Historicallyin the past, cell phone jammers were huge antennas mounted on trailers that had to be pulled behind a van. They now come in a variety of shapes and sizes including models that are about the size of a cell phone.