Abstract: A multi-sensor alarm system and method of protecting a premises include at least one sensor circuit and an alarm circuit which together establish a two-wire closed loop electrical circuit path in which a wide variety of alarm sensors are accommodated. The sensors include two-contact configurations which are normally-closed or normally-open, as well as multiple-contact configurations which are characterized by both normally-closed and normally-open contacts. Each sensor differently changes the electrical parameters of the circuit path; and the alarm circuit includes a transistor which senses each parameter change, and a timer which generates an alarm signal whenever any of the sensors is actuated. Opening or closing the circuit path at any point therein will cause the alarm signal to be generated. A status indicator constantly monitors and supervises the status of the sensors in the circuit path.