books.google.fr - Electronic monitoring (EM) is a way of supervising offenders in the community whilst they are on bail, serving a community sentence or after release from prison. Various technologies can be used, including voice verification, GPS satellite tracking and – most commonly - the use of radio frequency...https://books.google.fr/books/about/Electronically_Monitored_Punishment.html?id=Bo6xJwvZBo0C&utm_source=gb-gplus-shareElectronically Monitored Punishment