This story is over 5 years old.


‘This Is a War’: Prisons Want Cell Phone Jammers to Stop Inmates from Communicating With the Outside World

Prisons want jamming technology to stop criminal activity, but critics warn there would be dire consequences if jamming was allowed to propagate.
cell phone in jail
Between 2012 and 2014, more than 8,700 cell phones were recovered in federal prisons, according to FCC Chairman Ajit Pai. Image: Shutterstock

In June the Department of Justice released a report that declared a solution to prevent criminal activity from happening within prisons: it successfully tested a jammer that would block mobile signals from smuggled cell phones inside a Maryland prison.

Throughout the corrections world the news spread fast. For South Carolina Corrections director Brian Stirling, the news affirmed his beliefs: to stop the flood of mobile phones streaming into prisons, jamming technology was the best, cheapest, and most efficient way to go.


A jammer can be a small, inexpensive box that transmits a continuous tone to antennas, effectively stopping any cell phone from making or receiving calls. Jamming equipment is generally cheap—a Google search turned up dozens of options ranging in price from $119 to $650—and easily available to order online.

But critics warn there would be dire consequences if jamming was allowed to propagate. They argue that there are numerous nefarious reasons—money, control of new systems, and criminal motivations—behind the push to legalize jamming through the corrections system.

“If someone is advocating for new technology they probably know someone who sells equipment or has a piece themselves”

“Allowing jamming technology is a very slippery slope, and once that door is opened we can never turn back,” Ben Levitan, a North Carolina-based wireless communication expert who has advised correction facilities, told me by telephone. “I’ve been in this business for 30 years. If someone is advocating for new technology they probably know someone who sells equipment or has a piece themselves.”

Levitan and other technology experts interviewed for this article say there are other effective solutions to control the flood of cell phones in prisons, such as detection systems, which track, locate and identify radio signals, and managed-access systems, in which phone companies filter calls using a predetermined whitelist.


The bigger problem is the high cost of calls from prison, jamming opponents say, and the need for inmates to be in touch with their loved ones.

Read More: Idaho Prisoners Hack Tablets and Steal Nearly a Quarter of a Million Dollars in Credits

Inmates have had all sorts of creative ideas to bring in cell phones into prisons, corrections officials have long contended. In South Carolina, Stirling says, couriers have run through the woods and chucked backpacks of contraband over prison fences; drones have scoped prison yards, waiting until guards are out of the area before dropped cell phones into inmates’ hands.

“We need all our tools to go into battle”

Stirling has put 50-foot nets around his institutions, cut down tree lines so it is harder for drones to escape after a drop, installed high-level metal detectors, and supported the Department of Justice in numerous prosecutions of staff who smuggle in cell phones.

“This is a war,” Stirling told me in a phone interview. “We need all our tools to go into battle.”

Stirling’s “come-to-Jesus moment” was the shooting of one his correctional guards. On March 5, 2010, Captain Robert Johnson was home in Sumter, South Carolina, when a gunman broke in and shot him six times with a .38 revolver at close range. His attacker, Robert Odell Brown, 33, was murdered in February during an inmate fight at Lee County Correctional in Bishopville, South Carolina.


The hit was arranged by cell phone from Lee County Correctional. Since then, Stirling has barely rested in his quest to bring jammers into correctional facilities.

Stirling says roughly 4,000 contraband cell phones were confiscated in South Carolina correctional facilities in 2015. Between 2012 and 2014, more than 8,700 cell phones were recovered in federal prisons, said FCC Chairman Ajit Pai in a 2016 speech. That’s around 2,000 more than the next most common type of contraband—weapons. In one state prison, during a 23-day stretch, a detection technology logged more than 35,000 call and text attempts, Pai said.

Read More: Cell to Cell: How Smuggled Mobile Phones Are Rewiring Brazil's Prisons

One alternative to jamming, Levitan says, is small-box antennas, which are cheap (around $400) and can cover one block, which holds approximately ten cells. The boxes have to be wired together, but once the system is in place, all phones automatically connect to these antennas, and the signal can’t leave the enclosed yard. This type of approach has the ability to block calls as long as the facilities monitor the equipment, Levitan says, without the brute force of jamming technology.

Another option is managed-access systems, which the FCC is currently issuing licenses to test or install. Matt Caesar, an executive at GTL, an integrated technology company servicing corrections, says managed-access systems in a medium or large institution cost $750,000 to $2 million to install, depending on the logistics of the facility. The facilities provide a list of phone numbers, a whitelist, to the managed-access companies that can make phone calls from prisons. Then mobile phone companies, such as AT&T, Sprint, and T-Mobile, block the rest of the calls.


Last year, the National Institute of Justice issued a report on the success of managed-access systems at a Mississippi state penitentiary and a Baltimore city jail. Both facilities faced challenges fine-tuning the signals and monitoring the entire signal network, allowing holes in the blockage of calls into the prisons, and ultimately letting calls go in and out of the facilities.

Managed-access systems can be extremely expensive to maintain. Cell phone carriers frequently change their radio frequencies, which allow calls to enter the system. A corrections facility would have to pay for a technician to constantly monitor the waves and adjust the machinery, said Caesar. “It’s not really a viable solution for smaller places,” he said.

T-Mobile found in a 2018 study that operational costs between managed-access systems and jamming to be negligible, and overall managed access is a more versatile tool for cell phone blocking. The study found that to install any type of jamming, the correctional facility would need a precision-based system, which is more expensive.

Stirling is open to managed-access systems. He’s currently instituting a test at Lee County Correctional, where Johnson was shot, but doesn’t think it will be able to fully block all the calls.

“To me, these technology choices are either like having a wall or a door. A door some things can get through. A wall nothing can get through. What would you want?” Stirling said.


Although Stirling is a hardcore advocate of jamming, the reality of getting it off the ground is more difficult.

The Communications Act of 1934 outlaws jamming for any state or local entity and for personal use. The FCC says jamming creates serious safety risks; it can stop emergency information from reaching law enforcement and dilute radio signals on the ground.

From approximately 2009 to 2018, the enforcement bureau carried out 173 actions against people using jamming equipment, including fines ranging from a few thousand dollars to $25,000 and above and forfeitures of equipment, in addition to warnings and citations.

While organizations such as the National District Attorney Association, Department of Justice, and Tennessee and Florida Department of Corrections have been lobbying for jamming for years, it’s only since Pai became FCC chairman that the campaigns got an added push.

Read More: Americans Don't Care About Prison Phone Exploitation, Says FCC Official

In 2017, in a rare move, the FCC assigned a specific person to facilitate new license applications for correctional facilities to test and install managed-access systems. In February 2018, Pai convened another meeting on the topic, saying on Twitter he was happy the wireless industry was committed to taking a more active role.

An FCC spokesperson was not available for an interview, but instead directed me to previous statements and rulings.


CTIA, an association representing the US wireless communications industry, advocates for a more measured solution, such as a managed-access system or a court-order process to direct a wireless carrier to disable service to phones that correctional facilities identify as contraband. CTIA also developed a website, Stolen Phone Checker, that allows individuals and companies to check if a phone has been stolen.

New Technology, Questionable Uses

Jamming can be extremely effective if the signal is strong enough to cover the frequency range telecoms use to send signals over their networks, whether they use CDMA or TDMA bands, says Anthony Ephremides, an information technology professor at the University of Maryland.

“There really is no simple or practical way to a disable a jammer. In order to destroy a jamming signal someone would have to be extremely savvy and sophisticated technologically. It’s a huge advantage for jamming,” said Ephremides.

The problem is when jamming equipment falls into the wrong hands. NBC News reported on the growing use in organized crime of jamming equipment to disrupt GPS systems throughout Europe and Africa to smuggle drugs and traffic weapons. Simple criminals use jamming technology to disable garage doors and alarm systems.

The long-running battle, jamming critics say, is about money. There are two forces at play: a rush of companies developing technology and equipment under a public-safety premise for the $75 billion American corrections industry, and the ability to patent and distribute new technology with government approval.


Sascha Meinrath, the chair of telecommunications at Penn State University and the founder of X-Lab, a future-focused technology policy and innovation project, has doubts about what’s behind the push. He’s seen questionable rollouts before, particularly in the surveillance realm, where he says people now use equipment to track whomever they please. He cites the growing use of law enforcement and DIY trackers utilizing stingray devices, which mimic cell phone towers, to track people’s movements.

“Prisons are just easy use-test cases for private companies to demonstrate technology because it’s a vulnerable population”

In one instance, Motherboard reported on a Canadian prison that was using surveillance technology to record phone conversations and text messages of prisoners, staff, and people just passing the facility.

“This fight isn’t really about stopping cell phone smuggling into prisons,” said Meinrath. “There is money to be made. Prisons are just easy use-test cases for private companies to demonstrate technology because it’s a vulnerable population. As soon as its approved to work there, other venues will be clamoring to roll it out. Then where can we draw the line?”

In 2009, Meinrath signed a letter opposing S. 251, The Safe Prison Communication Act, which passed through the Senate but still sits in a House subcommittee. The bill calls for correctional facilities to obtain permission to use jamming technology to prevent illegal communications within their walls.


Meinrath, along with nine other critics, argued against jamming under any circumstances. They said that allowing any use of jamming would encourage a proliferation of jammers, affect public safety, and interfere with national communication.

“Outside communications can be a real issue, but jammers don’t solve this problem; instead, [jamming] creates incredible collateral damage,” said Meinrath.

Opponents also cited the use of private companies, such as Cell Antenna, lobbying the FCC to change the rules to make room for jamming equipment, and urged Congress to look at the underlying issues surrounding cell phone smuggling.

Caesar disputes the claim technology companies are trying to make money off the correctional systems. “We are not advocating for one solution or another. Our customers have a problem and we are trying to solve it with technology.”

Bianca Tylek, director of the Corrections Accountability Project in New York City, says illegal cell phones wouldn’t be a thing if calls from within prisons and jails weren’t so expensive. For inmates it is about reasonable-costing access to their loved ones.

Tylek worked on the campaign to persuade New York City Mayor Bill De Blasio to sign a bill passed by the council to make calls free from Rikers Island, the city’s jail complex. Calls made by Rikers inmates generate $8 million annually—with $5 million going to the city.

Each correctional facility contracts with a private telecommunications company to run and monitor calls through their system. The company collects the revenue for the calls and provides a portion of the profits to local governments. For example, pricing for a 15-minute call is $24.95 from Arkansas County Jail via Securus, and $17.77 from the Douglas County jail in Oregon via Global Tel*Link, reports Prison Policy Initiative, which filed an ex-parte submission with the FCC, publicly making available the call prices.

But she says the success in New York City would be harder to replicate in other localities without such a large corrections budget.

“We have two entities collecting revenue, and they will fight tooth and nail to make sure these things don’t disappear,” said Tylek. “They’d rather deal with smuggled cell phones than make calls free.” She suggests smaller municipalities should discuss how to replace their revenue and move towards a solution rather than repeating something that isn’t working.

Stirling wants inmates to be able to talk to their friends and family, but doesn’t see the possibility of free calls in South Carolina. “We have to pay for this. Correction is already underfunded, and it would be a huge, huge cost to the prison system to allow folks to talk on their free phones.”

He also doesn’t buy the argument that cell phone smuggling has risen because of expensive calls. “Our phone system is one of the least expensive in country—for a collect call it is ten cents a minute and for a prepaid call it’s eight cents a minute.”

For now, Stirling’s not giving up his fight to allow jamming in prisons. “How can I look at Captain Johnson and say, ‘Every prisoner has a phone’? Inmates are incarcerated physically and they need to be virtually as well.”

Listen to CYBER, Motherboard’s new weekly podcast about hacking and cybersecurity.