Jammer device to prevent mobile phone from detonating explosives

　　Terrorists have long used cell phones to launch improvised explosive device (IED) attacks around the world. While in some explosions the time lag between the trigger call and detonation was just seconds, a terror bomb in London took nearly an hour to detonate after the initial attack.

　　How terrorists use cell phones to remotely detonate bombs, how jammer devices disrupt this connection, whether law enforcement agencies need such jammer devices, and why they currently lack such jammer devices.

　　The extended time interval between triggering and detonation suggests that cell phone jamming devices can be used to prevent cell phones from detonating explosives.

　　The jammer device blocks cellular downlink frequencies and prevents the phone from answering incoming calls; however, it does not prevent the phone's alarm function from detonating the bomb.

　　One expert estimates that the jammer device can stop half of all cellphone bombs, as well as remote-controlled bombs that use other remote tools, such as garage door openers or toys.

　　There are separate devices that can attack event bombs using the cell phone alert function. U.S. federal law currently allows only federal law enforcement officers to use such jammer gps devices.

　　Because the federal government has been slow to respond to bomb detection at the local level, many local police agencies favor allowing the purchase and use of jamming equipment.

　　The Cellular and Internet Society is currently working with the U.S. Department of Homeland Security on an agreement that would retain federal authority to determine when and how jamming devices are used, while allowing a federal directive to allow local police to exclusively use jamming devices.