In an Enforcement Advisory issued in December 2014, the Commission reiterated that its regulations governing the use of so-called signal jammers provide no exemption for their use by school systems, police departments or other state and local authorities. Only federal agencies of the U.S. government are eligible to apply for authorization to use such devices.
Jammers are designed to block, jam or otherwise interfere with authorized radio communications by emitting radio frequencies that prevent wireless communication devices from initiating or maintaining a connection. Such devices can interfere with emergency 911 communications as well as communications between first responders, and are illegal under FCC regulations without express authorization. Violations of these regulations can result in monetary penalties of up to $122,500 for any single violation, and criminal sanctions including imprisonment.