A personal response system is a signaling device that summons help during an emergency. Although personal response systems vary widely, there are three components. The first component is the electronic hardware in the home, which consists of portable and installed sensors and the control console. The second component is the emergency response center, which is either provider-based or manufacturer-based. The third component involves the dispatch of appropriate assistance. The primary users of personal response systems are women in their seventies and eighties who live alone and who have cardiac and musculoskeletal problems, which make them prone to falls. The frequency of personal response system use varies from an average of 0.44 to 0.84 emergencies per subscriber per year. Program coordinators believe that personal response systems help to delay institutionalization, reduce admissions to hospitals, substantially shorten hospital stays, and reduce the duration of home attendant services. The most favorable impact of the personal response system has been its psychologic value to the users and their families.