These monitoring systems typically are composed of a centrally located control computer, a receiver unit in the offender's home, and a transmitter device worn by the offender. In using such systems, agencies must ensure that they comply with fourth amendment prohibitions against unreasonable search and seizure. In general, courts have held that the use of electronic devices is acceptable when there is no interception of wire or oral communication and when the device does not reveal information that could not be obtained by visual surveillance. Further, probation officers are authorized to conduct surveillance, and electronic monitoring merely enhances this ability. Similarly, there is no infringement of the probationer's right to privacy. Information obtained through electronic surveillance will only be used for purposes of revocation where no criminal act is involved, so it is unlikely to violate the right against self-incrimination. As monitoring is more humane than incarceration, cruel and unusual punishment challenges are unlikely. The equal protection clause, however, may result in difficulties if indigent clients are excluded from eligibility because they cannot pay program costs or fees. Overall, while electronic monitoring raises several constitutional issues, its use will most likely be upheld by courts, primarily on the grounds of diminished rights of probationers. 91 footnotes.