Infrared (IR) listening systems transmit sound by invisible light beams. An IR system converts an auditory signal into infrared light and carries - or emits - it by special light emitting diodes (LED) to the infrared receiver. The receiver converts the light energy back into an auditory signal....Diagram
The infrared signal is limited to line of sight transmission, so there is no spill over from room to room. This makes it a quite secure form of transmission used in conference rooms and courtrooms where confidentiality is a concern.
The personal infrared system is quite flexible and may be used in various modes with or without a hearing aid. It is not suitable for outdoor use because sunlight affects the transmission. Also bright incandescent light, especially reflector type spotlights, can be a cause of interference.
