Cellphone-Detector Circuit

This is a cellphone-detector schematic diagram figure 1

figure 1. Cellphone detector schematic diagram

The Bureau of Prisons lacks a sound evaluation plan for testing anti-cell phone technology deployed within federal prisons, says the Government Accountability Office.

Confiscation of contraband cell phones at some federal prisons is more than doubling each year, leading the federal government to increasingly look to technology as possible solution.

The Government Accountability Office, in a report dated Sept. 6--it's actually a redacted version of a report the GAO issued in July--says two federal prisons have implemented large-scale, sensor-based cell phone detection systems. But officials from the bureau's Office of Security Technologies told GAO auditors that the systems haven't been subjected to any evaluation assessing whether widespread adoption would be feasible and effective.

In other cases of cell phone detection technology testing, prison officials simply never informed OST that the test was occurring, leaving OST officials to hear about it only second-hand from vendors, GAO auditors say OST officials told them.

OST officials also said test results from different prisons can be inconsistent because the individuals conducting the testing can vary from a computer specialist to a correctional officer--individuals with different skills and knowledge levels.

The bureau says any anti-cell phone technology deployed within prisons cannot interfere with signals outsider the secure perimeter, nor can they collect information about end-user device utilization outside the perimeter.

Jamming strictly within the confines of a federal prison, however, is legally permissible so long as the prison has authorization from the National Telecommunications and Information Administration.

A December 2010 report from the NTIA says the bureau has generally concluded that existing anti-cell technology solutions have shortcomings, such as not detecting all commercial cellular signals, having a very short detection distance or being unable to affix the location of an active cell phone due to the amount of signal reflection caused by the huge quantities of metal inside prisons.

Hand-held detection devices suffer the failing of being easy for inmates to adjust to--they simply shut off the phones if they see staff coming with a portable device, the NTIA report says. Existing commercial solutions might also be too sophisticated or expensive for daily operation by a non-technical staff or just be impractical to implement in prison compounds that have large acreage and dozens of buildings, the NTIA report says.

In response to an NTIA notice of inquiry made in advance of the report, many wireless industry firms expressed concern over the potential for prison jamming to cause wider interference or possibly obstruct land mobile radio communications. Another commentator said testing conducted by the NTIA itself demonstrates that jamming can work without interference or compromising public safety.