Abstract: A remotely-monitored stored-audio security system has a local control unit at a monitored premises that communicates with a remotely located central control unit for alerting personnel of an alarm at the premises. Microphones located on the monitored premises receive sounds that are recorded on a recording device in the local control unit. When the alarm occurs the recording device ceases recording, thereby preserving any sounds that occurred prior to and immediately after the activation of the security system. A detector monitors the input to the recording device and detects the occurrence of a discrete sound, i.e., a sound exceeding the level of ambient noise. When the local control unit transmits the alarm indication it also transmits an indication to the central control unit for informing personnel whether any discrete sounds have been recorded.

Abstract: A security system which includes a master unit for communication with a central control station by telephone and provides for a plurality of remote detectors located in different zones of a secured area to be selectively wired. The remote detectors communicate through the main power supply with a master unit which is powered by the mains. Microphones in the remote detectors can be selectively operated through the master unit as activated by the central control station to listen in to different zones to permit for identification of a security breach in different zones. A high-volume output mode speaker phone is provided to the master unit. Feedback circuitry generates audible signals when the system is armed or disarmed remotely. Separate activation of interior and perimeter detectors can be effected.