A Typical Public Address System.

The Block Schematic opposite shows a simple public address system.

The system has three inputs:

  1. a radio for playing background music
  2. a microphone for staff announcements
  3. an input from a time control system for shift time signals

Four zones a catered for:

  1. Directors Suite
  2. General Office
  3. Production
  4. Warehouse

The radio plays music to the general office, production areas and warehouse.

The microphone, which over-rides the radio, can select each individual area for announcements or it can select all areas for global announcements.

Finally the time signals are broadcast only to the production and warehouse zones.