Abstract: An alarm system apparatus includes a plurality of sets of smoke or heat detectors located throughout a building. A plurality of automatic telephone dialers are also located in the building and each dialer has at least one set of smoke or heat detectors operatively connected thereto. A plurality of localized alarms are connected to the automatic dialer for actuation by the detectors and each automatic dialer is connected to a phone line into a microcomputer having stored thereon the position of each smoke and heat detector. The microcomputer, in turn, has a modem coupling it through the phone lines to a remote terminal. The microcomputer includes a connector for coupling a mobile terminal to the computer from the exterior of the building. In addition, the auto dialer is equipped with a relay for switching in an auxiliary battery supply in the event of power loss.