Incidents are inevitable in settings that lack physical barriers between staff and inmates and will put the safety and even the lives of staff members at risk. When an incident occurs, it is crucial both that it be reported and that its location be known. The traditional methods of reporting have included radio-frequency duress alarms, sonic or ultrasonic duress alarms, and sound level monitoring systems. The first two systems must be manually-activated, while the third may sometimes be considered to be a violation of inmates' civil rights. In contrast, adding a card-access system to the duress alarm system permits central control staff to know immediately who is in trouble, where they are, and how many other staff are nearby. In addition, the system automatically deletes cards that are associated with alarm transmissions so that inmates cannot use the cards. Another approach is to use intercom stations and television cameras to monitor the identities and numbers of inmates as they move from area to area. Together with the involvement of the staff, the use of these systems can improve staff safety both before and after an incident occurs.