A public address, or loudspeaker, system that is used to make annoucments, notify or summon people. In large buildings, paging systems commonly are divided into a number of zones, or coverage areas.Key telephone systems commonly feature voice-over paging, which allows an authorized user to page through the intercom system, which works through the speakers built into the telephone sets. 
A public address, or loudspeaker, system that is used to make annoucments, notify or summon people. In large buildings, paging systems commonly are divided into a number of zones, or coverage areas.Key telephone systems commonly feature voice-over paging, which allows an authorized user to page through the intercom system, which works through the speakers built into the telephone sets.