Phone jamming is about to get political. Everyone from police to governments are using simple devices that prevent people from making calls or texting in certain areas โ€” and they're doing it to control the flow of information. Let's take a look at these devices, their legality and current uses. Then we'll look at how this technology will be used against you in the future.


The simple science behind blocking your phone calls

Cell phone jammers work by transmitting radio waves on the same frequency used by your digital cell phone. By emitting such a signal, communications between your phone and a cellular communications tower is disrupted.

In the United States and South America, most digital mobile phones operate on a a 1.9 GHz frequency band, while 900 Mhz and 1.8 GHz bands are used across most of Europe and Asia. Even if your phone operates on multiple bands, manipulation of a single band is enough to cause a call to fail by disturbing the outgoing call or incoming voice data.


Pocket-sized jammers are available for sale online if you do a little searching, and schematics are readily available as well. These small jammers work in a 8 to 10 meter radius, while larger generators need a truck to move them, but they are capable of blocking communications within a 5 kilometer radius.

Is it legal?

Creating a small device to continually transmit a signals between the 900 MHz and 1.9 Ghz bands is not difficult, but it is currently illegal to use such a device in the United States due to a nearly eight decade old set of laws, the Communications Act of 1934. Thanks to the Communications Act of 1934, the Federal Communications Commission (FCC) can license the 1.9 Ghz (and other bands) to cell phone companies for commercial use, with a deliberate blockage of is viewed as a denial of service.


Possessing a radio frequency jammer in the United States is not a crime, but using the jammer is illegal, making these signal emitters yet another member of modern society's "legal to own, illegal to use" fraternity. If caught, offenders face jail time and a $16,000 fine in the United States for infringing on the communication rights of others. New Zealand, Canada, and the United States allow use of the jammers by law enforcement agencies and in prisons.

Blocking cell phone data transfer is an all or nothing situation โ€“ as of now, one cannot create a device that blocks personal calls but allows emergency calls to be made. The denial of access to emergency services is a sticking point in several attempts to place the jammers in schools in the United States and Canada.


How are phone jammers being used today?

Cell phones are commonly used in prisons, however, the items are illegal in U.S. Federal prisons. Cell phone jammers are used by prisons to block calls, preventing coordination of gang related activities within the prison and preventing unauthorized communication with the outside world.

Jammers also play a role in providing security during transportation of high level officials. U.S. Presidential motorcades make use of the devices, and a cell phone jammer played a role in foiling a 2003 assassination attempt on Pakistani President Musharraf. Cell phones are common triggers in improvised explosive devices, with jammers sometimes preventing detonation.


In France and Japan, use of cell phone jammers is legal in movie theaters, art galleries, concerts, and other public venues.

Who will kill your phone tomorrow?

A Philadelphia, Pennsylvania man is taking responsibility for cleansing the air of loud mobile calls by operating a cell phone jammer on buses and in other public places when annoyed. So far the individual has not been charged with any crime.


Several theater chains are becoming vigilant in preventing cell phone use during a movie - could small radius jammers be a safe and physically unobtrusive alternative in these situations? Granted, the glow from a cell phone is almost as annoying as the accompanying conversation, but blocking phone transmissions within parts of a large public venue does not prevent communication of wide-scale emergency alerts, as long as the entire area is not blanketed by jammers.

But once we accept the use of jammers in public venues for our personal benefit, do we open the door to the intrusion of jammers in traditionally private realms? The technology to prevent the use of cell phones is readily available and already comes in a small package - a future where every car comes with a pre-installed jammer to block your smart phone's operation once the car starts moving is believable.

Several cities ticket drivers for using a phone while a vehicle is in motion - the in-car installation of jammers would take this action a step further, and prove this current ticketing practice is not just a means of acquiring additional revenue.


It is quite easy to see cell phone jammers installed in the majority of theaters, concert halls, sporting events, and religious venues within the next decade. Personal use of handheld jammers is likely to remain in a grey area, as the use of such equipment infringes on the rights of others and could be used to block communications prior to criminal activity, much like the physical act of cutting a telephone line.

The wide-scale implementation of mobile phone jamming technology has its benefits, but these benefits come along with direct infringement on your personal rights by denying a service you pay to maintain twenty-four hours a day. The denials would definitely cause alarm and a feeling of helplessness in many situations - the anxiety felt after cutting the umbilical chord between you and your smart phone.


The top image is by Kopessius/DeviantArt, with text altered. Image of the Wavebubble portable jammer via ladyada/Flickr, the mockup of the TRJ-89 long range jammer is courtesy of EOD, and the map of wireless carrier dead zones in the United States is courtesy of Deadzones. Sources linked within the article.