In a jam: faced with terrorist threats, law enforcement could force a shutdown of cell phone service.

Large public gathering places in the Los Angeles area could be subject to temporary shutdowns of cell phone service under anti-terrorist plans being formulated by law enforcement officials.

"There may come a day soon, very soon," when the authorities would use cell phone jamming devices to shut down all service in places such as Los Angeles International Airport, Disneyland or Universal Studios, said Los Angeles County Sheriff Lee Baca, speaking at a recent public gathering.

Asked to elaborate, Baca declined comment through a spokesman.

But Catherine Deaton. Los Angeles district director for the Federal Communications Commission, said the controversial measure is being considered by law enforcement agencies. "I've heard they have the capability ... and they're looking at the utilization of it in Los Angeles for emergency purposes." she said.

John Miller, head of the LAPD's counter-terrorism bureau, did not respond to phone calls and questions faxed at the request of his office.

The use of cell phone jammers--portable devices that range in size from hand-held to suitcase-type--is banned in the United States, and the FCC can fine violators up to $11,000 each day per device. The FCC allows rare exceptions for police agencies, Deaton said, and enforcement is done on a case-by-case basis. The commission does not ignore the rules but does account for public safety concerns when looking at a violation, she said.

Wireless providers have fought against the introduction of jamming equipment, which is in routine use in many other countries, not only by governments but by commercial users.

Phones as triggers

Two recent examples have highlighted the use of cell phones to detonate bombs. The March 11 railway bombings in Madrid were triggered by calls placed to cell phones attached to the explosives.

And Baca, who recently returned from a fact-finding trip to Pakistan, described to the congregation at Sinai Temple in Westwood how Pakistani President Pervez Musharraf narrowly avoided a Dec. 14 assassination attempt thanks to a jamming device in his motorcade.

A bomb exploded moments after his limousine passed over a road bridge close to the capital, and Pakistani intelligence officials claimed that the jamming device delayed the cell phone detonator long enough to allow Musharraf to pass without injury.

Foreign governments, especially in the Middle East, have long used cell phone jammers to thwart assassination attempts and to safeguard locations such as mosques. France and Japan even use the jammers in restaurants and theaters, not for anti-terrorism, but to prevent bothersome ringing.

The reluctance by the United States to embrace the technology has mostly been framed as a civil rights issue, said security industry specialist John Mack, chief executive of USBX Advisory Services, based in Santa Monica.

"It's limiting people's ability to communicate," Mack said.

But the idea of shutting down localized service during specific terrorist threats is not farfetched.

Wireless Technology Inc. in Ventura has been selling cell phone blockers to the federal government since 1988. Although its president, Dan Fancher, is not aware of any state or local law enforcement agencies currently using cell phone jammers, he said the technology is readily available and frequently used by the military and the federal government.

The Secret Service, for example, uses jammers to protect President Bush in his limousine, on Air Force One, or while he is giving a speech. Cell phone signals are blocked for a half-mile around his location, Fancher said.

He said other applications include the FBI jamming a kidnapper's cell phone during a hostage situation or a bomb squad jamming the area around a suspicious object.

"There are all sorts of uses. It's just a tool for law enforcement," Fancher said. "This stuff flies under the radar. It's there, but it's not obvious."

He said the U.S. military has used cell phone jamming technology frequently in Iraq.

The jammer, which works on 28 volts of power, can jam all cell phone signals within a 10-mile radius of the device. Cell phones operate with two frequencies, one that receives and one that transmits. The jammer sends out a signal that overtakes the receiving frequency, therefore preventing a cell phone attached to a bomb from sending out an electrical charge.

The jammers do not affect wireless Internet connections, and cell phone users would not know the cause of the service disruption, only that they do not receive a signal. During the time that the jammer is on, users cannot receive calls but will still get messages from missed calls.

Industry opposition

Travis Larson, spokesman for the Cellular Telecommunications & Internet Association, said the wireless industry would be tolerant of limited use of cell phone jammers. "Certainly if law enforcement can use them to save lives, that use becomes more important than your average cell phone call," Larson said.

But he said the industry would become more concerned if law enforcement agencies in Los Angeles started using jammers on a regular basis, especially because California is such a large market for cell phones. As of December 2002, there were 17.4 million wireless consumers in the state.

"Jamming cell phone signals isn't fair to consumers who expect to be able to use their cell phones," Larson said.

Mack said there are civil rights issues involving citizens' rights to use their own property and other public safety issues that would crop up should cell phone jamming come into broader use by local law enforcement. "The minute you do this, you're going to have someone trying to report a rape at the same time," he said.

Fancher also said jammers should only be used by responsible people in tough situations.

"There will never be a proliferation of cell phone jammers in the U.S.," Fancher said. "This is a specific product for a specific problem. It won't ever be a commodity product."