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Managed Access Systems Can Prevent Contraband Cellphone Use

If contraband cellphones make it into a facility, managed access systems can prevent their use.
Date Published
July 30, 2017

Surprise searches, cellphone sniffing dogs, and metal detectors all play a role in the fight against contraband cellphones in corrections facilities, one of the most significant problems facing corrections administrators today.

Managed access systems are another means to combat the problem of contraband cellphones, one that can work even when other means are defeated. Rather than relying on keeping contraband phones out of a facility, managed access systems can keep those phones from being used. The systems allow calls from approved phone numbers while blocking calls to and from devices or numbers that are not approved.

Unlike jamming, managed access denies service to a select group of users, rather than to all users, and the technology is unable to stop the use of Wi-Fi to access the internet. Even so, loss of the ability to make calls or send text messages has the potential to make the contraband cellphones less valuable and reduce demand[1].

A managed access signal presents as an extension of nearby commercial cellular networks, allowing it to capture transmissions from cellular user devices. Once captured, unique identifying information is compared against a list of known authorized devices, and only transmissions from devices on this “white list” may go through.[2]

Recognize two notes of caution regarding the deployment of a managed access system: (1) they do require FCC approval and carrier consent for deployment and (2) they have the potential to cause interference outside of the prison or to adjacent bands unless properly designed.

Researchers from Engility Corporation, in its role as the host of the NIJ-funded NLECTC Communications Technology Center of Excellence,[3] and the School of Public Affairs at Indiana University-Purdue University Indianapolis performed case studies of how administrators implemented managed access systems at two vastly different correctional facilities: The Baltimore City Detention Center and Metropolitan Transition Center in downtown Baltimore, which are among the oldest and largest municipal jails in the nation, and the Mississippi State Penitentiary, located in the Mississippi Delta in a rural area near Parchman.

In the case studies, researchers detail how each facility approached the challenges of implementing managed access. In Baltimore, it was necessary to block signals in a tightly defined area, so administrators implemented a Distributed Antenna Signal (DAS) system. In Mississippi, the facility’s remote location allowed officials to throw up a larger “umbrella” system.

Both faced similar challenges in fine-tuning the signal, refining the approved devices list, and establishing good working relationships with commercial carriers. Also, corrections facilities tend to be made from materials that block and reflect signals in ways that are difficult or impossible to predict, creating “holes” in network coverage.[4] Also, facilities must harden managed access system hardware and associated infrastructure to prevent damage, system failure, and system inefficiencies from both inclement weather and premeditated attacks by incarcerated persons.

In spite of these challenges, the technology does appear to stop a significant number of calls and text messages from going through[5]

Managed access systems are not a be-all and end-all solution, but rather are one more piece of the puzzle to mitigate contraband cellphone usage.

About This Article

The work described in this article was supported by NIJ cooperative agreement number 2010-IJ-CX-K023, awarded to Engility Corporation, which operated the NLECTC Communications Technology Center of Excellence.

This article is based on the reports “A Case Study of Mississippi State Penitentiary’s Managed Access Technology,” (pdf, 102 pages) and “Analysis of Managed Access Technology in an Urban Deployment: Baltimore City Jail Complex” (pdf, 28 pages).

Date Published: July 30, 2017