SERVICE OFFERED: SUPPLY, INSTALLATION AND MAINTENANCE (AMC) for PUBLIC ADDRESSVOICE ALARMTALK BACK SYSTEMS PUBLIC ADDRESS SYSTEM(PA SYSTEM) is an electronic sound amplification and distribution system with a microphone, amplifier and loudspeakers, used to allow a person to address a large public. TALK BACK SYSTEMEMERGENCY VOICE COMMUNICATION SYSTEM(EVCS) for use as a fire telephone system, disabled refuge call system or as a combined system when both fire telephone and disabled refuge points are required. An EVCS is a fixed, bidirectional, full duplex voice communication system.