A multi-channel infrared telephony demonstration system for public access applications

Discusses the application of free-space optical links for public access (Telepoint) telephony service. The design considerations for such an application are described which lead to the selection of a modulation scheme and architecture for an experimental demonstration system. Some novel techniques for improving performance, including extending range and limiting interference, are presented. The performance of the demonstration system, built by MPR Teltech Ltd in conjunction with Light Ideas Inc., is described and compared with theoretical predictions and simulations. From this comparison some architectural and design recommendations for the product version of the equipment are presented.<>