NEW YORK – A cafe customer fed up with cell phone jammer chatter sits in a blissful bubble of silence as nearby customers laugh at the dead handsets.
A man tries to take a secret snapshot with his camera phone, but only gets a blank screen.
A priest infuses his church with new energy – the electromagnetic type – to keep his sermons serene and free from beeps, chirps and rock tones.
These are glimpses to a war of gadgets playing quietly around the world.
While millions of people embrace the freedoms of mobile communication, some people and businesses are turning the tide. They fight technology with technology, using detectors, jammers and other gadgets to defend privacy, security and sometimes mental health.
Scrambling a cell phone, essentially a two-way radio, is relatively simple.
Jammers generally disrupt communication between handsets and cell towers by flooding an area of interference or by selectively blocking signals by broadcasting on the same frequencies as those used by telephones.
Some jammers may need to be as smart as cell phones, which are trying to increase power or jump to other radio channels to avoid interference.
Depending on their power, the jammers can disrupt communications in an area extending over a few meters or several kilometers. Commercial jammers have been sold overseas for years, and some Internet publications even offer instructions on building homemade models.
The Federal Communications Commission prohibits persons in the United States from constructing, selling, operating or importing radio jamming devices. People who break this provision of a 70-year-old communications law face up to a year in jail and fines of $ 11,000 for each violation.
However, FCC officials say they have received very few complaints about the blocked mobile phones and have never taken action against anyone for the violation.
Those in the jamming industry say that individuals use low-power devices without fear of reprisal because it is difficult, if not impossible, for a caller to distinguish between a scrambled signal and a normal cell phone dead zone.
Despite this, US law discourages the use of the frequency jammer and limits its spread among consumers, said Kagan, the analyst. The wireless industry says jamming devices are putting the public at risk.
“One hundred and fifty million Americans rely on wireless phones, doctors may miss hospital calls, or parents may miss emergency calls from babysitters,” said Travis Larson, spokesperson for Cellular Telecommunications. and Internet Association.
Larson said that to reduce the inconvenience of using the cell phone, customers should use their “mute button, volume control, vibrate mode, voicemail and an on / off button” if applicable.
He said that jamming a specific area where silence is expected, like a movie theater, is always a risk, even with warning signs. “The jammers can sink into other adjacent frequency bands, blocking public safety radio signals used by police and firefighters,” he said.
But security concerns, courtesy suggestions, and the law haven’t stopped people from buying jammers.
He added that some business people also use jammers to keep meetings quiet or to turn off potential eavesdropping devices, especially cellphones faked to be bugs.
Although also illegal in England, jammers are more widely used