Abstract: A system for automatic detection of the presence of intrusion by an intruder and/or the phenomenon of combustion manifested in light, flame, and heat, and having delay before activating alarm means for preventing non-genuine detection is provided using digital, solid-state circuitry modules thereby facilitating installation, maintenance, and expansion of the system. An electronic combination lock coupled to the system controls the system to enable the detection of intrusion to be amended by the proprietor of an enclosure protected by the system. Separate alarm means having unique alarm sounds for intrusion and the phenomenon as well as optional telephone dialing of appropriate responding agencies is provided.