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Electronic Monitoring Equipment

NCJ Number
Date Published
7 pages
This pamphlet describes the four types of electronic devices for monitoring an offender's presence in a given environment and presents the National Institute of Justice's latest information on manufacturers and distributors of the equipment as of February 1987.
Three types of devices use a telephone at the monitored location. One type involves a miniaturized transmitter strapped to the offender which broadcasts an encoded signal at regular intervals. A central receiver accepts reports from the receiver-dialer over telephone lines, compares them with the offender's curfew schedule, and alerts corrections officials to unauthorized absences. A second type uses a computer programmed to call the offender during the hours being monitored. Various devices are used to ensure the offender's identity in receiving the call. A third type uses a transmitter worn by the offender. The locator, placed in the approved location, receives the signal from the transmitter, records it, and relays the information by regular or cellular telephone to the local area monitor. The fourth type does not use a telephone, as the signal from the offender's transmitter is received when the monitoring officer drives within one block of the offender's home.