Combined communication, security and alarm radio system

Abstract

A combined communication, security and alarm radio system for supervising equipment in a plant or installation, in which a base transmitter/receiver (4) is in two way communication with a remote control unit (2). A plurality of portable transmitter/receiver units (12) enables direct communication between operators through the base transmitter/receiver unit (4). An alarm message unit (8) connected to both the control unit (2) and a telephone exchange landline enables pre-recorded messages to be transmitted in sequence to a plurality of subscribers. Each portable transmitter/receiver unit (12) has a push button (27) to activate the alarm message unit (8) through the base transmitter (4) each being recognizable by its own tone. The system also includes a paging transmitter (6) and up to as many paging receivers (14) as there are portable units (12). A plant alarm unit (10) is automatically activated when failure or malfunctioning of equipment occurs or when there is unauthorized entry, this causing the paging transmitter (6) to operate instantaneously and the alarm message unit (8 ) to operate after a predetermined delay.

Dependencies are inferred from the claim text.