Countermeasures to Contraband Cell Phone Use in Prisons.ppt by handongqp


									Countering Contraband Cell
  Phone Use in Prisons
   A Technical Explanation of
    Available Technologies
           Electronic Sniffers
• Sniffer emits low power radio signal and
  detects reflections from nearby electronics
  – Must be close to the cell phone to detect it
  – Detects cell phones whether they are on or off and
    does not depend on frequency band

               Emits Signal


            Detects Response
                   Passive Detection
• Listens for cell phone signals
  –   Only detects a cell phone when it is active
  –   Calls can be connected
  –   Network of sensors triangulate cell phones
  –   Hand-held detectors are also available
        Detector                Detector

                    Detector                System Provides
           Prison Building Footprint       Location Of Devices
• Jamming is the deliberate radiation for the purpose of disrupting use
  of electronic devices, equipment, or systems
• Cell Phone Jammers:
    – Are frequency band specific, transmit on same radio frequencies as the cell
      phone to overpower desired signals and disrupt link between phone & tower
    – Do not discriminate among cell phones within range of the jamming signal –
      both contraband and legitimate cell phones are disabled

           Jammer                    Jammer

                                All Calls
                                Blocked                 Radio Signal

                                                     Can be a Network of
                                                    Individual Jammers or
            Prison Building Footprint                 Use “Leaky” Cable
    Inmate Call Capture Technologies
•   Effectively a mini-cell site
•   Impermissible calls are not connected (blocked)
•   Permissible calls are released and connected as usual
•   Policies selectable by system administrator
•   All 911 calls can be connected

                                       Captured & Released

                                       Prison Managed        Permitted Calls
                                       Access Cell Site     Connected to Cell
        Prison Building Footprint    Blocks impermissible   Network As Usual

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