This part of IEC 1603 gives methods of measuring and specifying the common technical features of the parts of systems which use diffusely radiated or wide beams of infra-red radiation as carriers of information, mainly representing audio and/or video signals but also control data related to audio and video apparatus. This standard applies to signal transmission by use of freely radiated infra-red, normally used indoors in rooms and for groups of varying sizes. It does not cover security systems or other industrial applications, such as measurement and automation equipment. It also does not cover traffic systems or systems for the help of handicapped people. Narrow-beam and cable-like infra-red applications are excluded, although the former could interfere with the systems covered.