Records are stored, retrieved, and compared to real life readings before a person is identified. There is a diversity of methods that measure and compare such human characteristics as fingerprint patterns, hand shape, pattern of the retina of the eye, acoustic voice pattern, or shape and timing of the individual's signature. Overall, biometric systems are easy to use nonthreatening, and relatively accurate. The simplest equipment configuration includes a reader, cable, and controller box on the secure side of the door. The host computer usually contains controller intelligence. Users key in a personal identification number so the biometric unit can retrieve the stored coding that represents the person's characteristics for comparison. If there are sufficient similarities, access is awarded. Some units output to an alarm system if access is denied. Available units vary in their verifier, availability of a card interface, user limit, and verify speed. Most equipment can operate in a stand-alone mode or be networked. In addition to providing access control, biometric systems can perform other tasks such as time and performance monitoring and transaction verification. Photographs and 1 table.