A public address system, commonly known as a PA system, is an electronic sound amplification and distribution system used to amplify a person's voice or other audio signals. The term 'public address system' is often abbreviated to PA system. Tannoy is a brand of loudspeaker that is commonly used in PA systems. C-SPAN is a cable television network in the United States that provides coverage of political events and public affairs programming. Squawkbox is a type of intercom system that is used to broadcast announcements over a loudspeaker.