Two major systems are currently available. The random-calling system monitors offenders through random telephone calls and a beeper alert system that notifies probation staff of violations. The other system, continuous signaling, monitors offenders through a radio frequency signal. Both usually involve the offender's wearing an electronic bracelet-like device on the wrist or ankle. An electronic incarceration program in Virginia uses random calling and continuous signaling with carefully selected offenders. Offenders and their families have responded well to the program, and violation rates have been low. A survey of 14 electronic monitoring programs shows they are being used with various types of offenders, including juveniles and high-risk offenders. In some jurisdictions, monitoring is supplemented by intensive supervision. Nationwide, such programs have shown promise -- reducing costs, saving prison space, and resulting in low violation rates. Photographs.