"Managed access" creates an umbrella over the prison, blocking transmissions from all but pre authorized phones, according to SCPR.org.
It’s paid for by Global Tel Link, the same company that operates the state prison’s payphones. They hope to recapture inmate customers who’ve increasingly turned to contraband cell phones to keep in touch with the outside world.
But a report by the nonpartisan California Council on Science and Technology raised concerns about the efficacy of the technology, including that it doesn't block 4G or satellite transmissions.
It also cited a case where a Mississippi prison tried the technology and found it lacking.
The report suggests that correctional officers be screened for contraband before starting their shifts, though the California Correctional Peace Officers Association has said that kind of screening would violate correctional officers’ contracts.
Jeffrey Callison with the California Department of Corrections and Rehabilitation said that no one approach to combating contraband is perfect, but managed access is a free-to-taxpayers technique that can supplement other methods such as phone-sniffing dogs and higher penalties for those caught with phones.