Abstract: A scanning control system is disclosed for remotely sensing or monitoring a predetermined condition or state, such as the presence of a fire, by means of one or a multiplicity of detecting stations at one or a multiplicity of locations with each detecting station providing a positive indication of the location of each predetermined condition sensed. A scanning or control panel is electrically connected with the detecting stations by means of four wires extending from the panel regardless of the number of detecting stations utilized in the system.