This invention relates to the zonal transmission of data by optical means through the modulation of light from common building light fixtures, including the light output of fluorescent, mercury vapor, and other arc or discharge lamps and fixtures; a system for the reuse of radio frequencies by smart radios, and the accurate locating and tracking of objects or persons as they move through a building; by means of creating a communications system which exploits the existing infrastructure of a building to facilitate the transmission of relatively secure control and communications data via creation of a multiplicity of area-limited interference-free communication zones. The system facilitates the transmission of wide-area as well as zonal-specific data. The system facilitates the creation of a database that contains present location and history location and movement data of persons and objects as they move through a building.