Countering Contraband Cell Phone Use in Prisons

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Countering Contraband Cell Phone Use in Prisons

• A Technical Explanation of Available Technologies

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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
Sniffer
Detects Response
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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 Location Of Devices
Prison Building Footprint
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Jamming

• 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 Generator
Can be a Network of Individual Jammers or Use
Leaky Cable
Jammer
Prison Building Footprint
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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
Permitted Calls Connected to Cell Network As
Usual
Prison Managed Access Cell Site Blocks
impermissible Calls
Prison Building Footprint