By Bryce Peterson, Ph.D., and KiDeuk Kim
Data show that tens of thousands of contraband cellphones are recovered in prisons across the United States — more than 25,000 across 20 states in a single year. These devices pose a significant threat to public safety and the security of correctional institutions, as they can be used to coordinate drug trafficking, escapes and other criminal activities.
While there are many technologies that help find and disable contraband cellphones, no single technology has yet proven reliable enough to fully address the problem across diverse facility environments. As a result, many correctional leaders view cellular jamming technology as a potentially valuable addition to the broader toolkit for addressing contraband communication. The problem is that under the Communications Act of 1934, state and local agencies are not permitted to intentionally interfere with radio communications.
That policy landscape may soon shift. The Federal Communications Commission recently proposed new rules that would permit prison and jail officials to use jammers. This decision is being hailed by both correctional authorities and lawmakers as “the answer” to the cellphone problem and as a way to “calm prison chaos.”
Evidence from research
While jamming may be another useful tool in the fight against contraband, it is unlikely to be a cure-all. A comprehensive and sustainable solution will require far more than any single technology. A couple of years ago, we published a report on the potential uses, efficacy and implementation challenges associated with jamming. This report synthesized current knowledge around jamming, drawing upon interviews with correctional authorities who had direct experience testing and using this technology both within the United States, where the Federal Bureau of Prisons has been exempted from the prohibitions in the Communications Act, and abroad, where jamming has long been used in prisons.
Our findings suggest jamming can block signals effectively but requires careful oversight. Like any other technology, it requires frequent monitoring, maintenance and calibration. Jammers need to be set to the specific frequencies of all available networks in the area and regularly checked to prevent signal bleed into nearby communities. Given these operational demands, alongside the underlying cost of the hardware itself, it is understandable that jammers for most medium-to-large facilities typically cost between $1.5 million and $2.5 million per facility.
Technical and practical limitations
Jamming also has practical constraints. Physical infrastructure and facility design can create areas where the jamming signal is less effective, generating potential gaps in coverage, particularly in reinforced structures or large open-air spaces. For this reason, some agencies may prioritize jamming in indoor areas such as housing units and dining areas while considering alternative strategies for outdoor areas.
Moreover, the idea that jammers can render cellphones completely useless as “bricks” or “expensive paperweights” should be viewed with caution. While jamming disrupts cellular signals and potentially Wi-Fi or satellite frequencies, other features of the phone still work, posing continued safety concerns. Phones can still be used to take and share videos and photographs of a sensitive or private nature or to smuggle harmful materials such as child pornography into facilities for distribution.
Jammers versus managed access systems
Jammers have advantages and disadvantages compared to other technologies already used in prisons. Managed Access Systems intercept illicit cellular signals rather than jamming them. While MAS suffers from many of the same challenges as jamming, including costs, calibration requirements and dead spots, they allow officials to whitelist authorized phones used by prison personnel as well as any call made to an emergency number.
MAS also captures data that can identify the specific phone and SIM card being used in the illicit call, including the International Mobile Equipment Identity and the International Mobile Subscriber Identity. This information offers critical insight into how many devices are being used and can inform staff efforts to find and confiscate them. Jammers, conversely, do not produce actionable intelligence.
Recent processes established by the FCC have also made MAS and other technologies that intercept identifying data from cellphone transmissions more effective. Correctional officials can now provide captured transmission data to wireless carriers, who will permanently disable both the phone and the SIM card. Unlike jamming, this process truly bricks the phone and does not need to be foolproof to be effective. As long as authorities intercept some transmissions from a contraband phone, they can quickly and completely render it useless.
This capability can serve as a meaningful deterrent against purchasing a device that can cost up to $3,000 on the prison black market. There is no comparable consequence associated with jammers.
Policy and implementation considerations
The FCC’s proposal marks a pivotal moment in prison security policy. Jamming technology could become a long-awaited and valuable part of the corrections toolkit, but it will not, by itself, end the contraband cellphone problem. Real success will depend on strategic implementation, ongoing evaluation and coordination among technology providers, correctional agencies and regulators.
As the FCC finalizes its jamming rule, correctional leaders should carefully weigh trade-offs related to effectiveness versus intelligence, the high capital and ongoing maintenance costs, legal oversight risks associated with interference beyond facility walls, the influence of facility design on coverage and the potential value of integrating jamming with MAS or detection technologies to achieve more durable results.
About the authors
Bryce E. Peterson is a senior research scientist in the Center for Justice Research and Innovation at the CNA Corporation. He leads a portfolio of research and technical assistance projects focused on correctional policies, institutional safety and security, and technological interventions in criminal justice settings. He received his Ph.D. in criminal justice from the John Jay College/The Graduate Center, City University of New York.
KiDeuk Kim is a senior fellow in the Justice and Safety Division at the Urban Institute, where he leads the Justice Systems Data and Analytics team. His current work centers on innovative uses of data, analytics and artificial intelligence to inform operational decision-making and technology-enabled justice system interventions.