Electronic Monitoring

Programs and Technologies

Electronic monitoring programs are run by state departments of corrections, local courts and law enforcement agencies, and private contractors, depending on the jurisdiction in which the program is run. There is a great deal of variation in the administration of this penal strategy. For example, programs may target specific populations, and offense types, and vary in their hours of operation. Some charge the offender a fee, while others do not.

Electronic monitoring exists at all stages of the criminal justice system from pretrial to postrelease supervision. Thus, surveillance may be used as (1) an alternative to pretrial detention, (2) a sanction meted out at time of sentencing, (3) an alternative to custody that is offered postsentencing, (4) a tool to ensure compliance with a work release program, or (5) a condition of probation or parole.

There are two main types of monitoring technology currently in use: continuous signaling and programmed contact. Continuous signaling involves the use of three devices: a transmitter that is worn by the offender on the ankle or wrist, a receiverdialer attached to a telephone in the monitored location, and a central computer that receives the transmitted information. The transmitter sends signals to the receiver-dialer, which contacts the central computer at the monitoring center whenever there is a change in the offender's status (entering or leaving the monitored location). The offender's approved schedule is stored within the central computer, allowing for a comparison between the signaled change in status and the offender's schedule to ensure compliance and detect violations.

Programmed contact technology involves the use of equipment that initiates periodic telephone calls to the location under surveillance (usually the offender's home) to verify the offender's presence. Verification may occur by having the offender insert a worn device, or wristlet, into a verifier box that is attached to the phone. This is known as an “electronic handshake.” Verification may also be established using voice verification technology, video verification, or by having the offender call an 800 number and typing in a random code provided by a device worn by the monitored person to establish ID.

For individuals who do not have a telephone, a drive-by unit may be used for monitoring purposes. A transmitter worn by the offender will send out signals that an officer can receive by tuning a receiving device into the frequency of the monitor. The person will not be aware of when checks are being conducted.

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