The US Federal Bureau of Prisons recently ran a test for jamming contraband cellphones in a South Carolina state correctional facility.“Micro-jamming,” or disrupting phone signals within a very precise area, was tested in a federal prison last year.But this test signaled that state prisons — which generally don’t have the authority to mess with phone signals — could be on their way to using the technology.The test was held last week at the maximum-security Broad River Correctional Institution in Columbia, South Carolina.According to the Associated Press, it lasted five days and involved jamming signals in a housing unit.The National Telecommunications and Information Administration (NTIA), which oversaw the test, will analyze the results and release them in a report.