Conventional systems are hardware-based and use analog technology. Conventional fire alarm systems are made up of zones. Multiple devices, both initiating and notification devices, make up a zone which connect to the main control panel. Conventional systems are analog in that they use electrical currents to communicate with the control panel.

Because a conventional system relies on individual circuits to communicate with the control panel, the information the panel can receive is limited to the number of devices it can support. The information is also limited in the sense that it only tells the panel whether a device has been activated or removed, not which device or where.

A public address system (PA system) is an electronic system comprising microphones, amplifiers, loudspeakers, and related equipment. It increases the apparent volume (loudness) of a human voice, musical instrument, or other acoustic sound source or recorded sound or music. PA systems are used in any public venue that requires that an announcer, performer, etc. be sufficiently audible at a distance or over a large area. Typical applications include sports stadiums, public transportation vehicles and facilities, and live or recorded music venues and events. A PA system may include multiple microphones or other sound sources, a mixing console to combine and modify multiple sources, and multiple amplifiers and loudspeakers for louder volume or wider distribution.

Simple PA systems are often used in small venues such as school auditoriums, hospitals, and offices. PA systems with many speakers are widely used to make announcements in public, institutional and commercial buildings and locations—such as schools, stadiums, and passenger vessels and aircraft. Intercom systems, installed in many buildings, have both speakers throughout a building, and microphones in many rooms so occupants can respond to announcements. PA and Intercom systems are commonly used as part of an emergency communication system.