Abstract: A security system wherein a plurality of locations are monitored by sensors which transmit alarm signals to a central control station by radio or telephone, each alarm signal being encoded to identify the particular sensor location and alarm condition. The control station comprises a computer which correlates the received alarm signals with information stored in the computer memory to identify which of a plurality of satellite stations are to be notified of a particular alarm condition at a particular monitored location, what correlated information is to be transmitted to such satellite station, and whether to effect such transmission by radio or telephone. The computer actuates a radio or telephone transmitter in the control station to transmit correlated signals to the appropriate satellite stations, and may also actuate a speech synthesizer so that such signals may be transmitted as synthetic speech.