A radio reading service or reading service for the blind is a public service of many universities, community groups and public radio stations, where a narrator reads books, newspapers and magazines aloud for the benefit of the blind and vision-impaired. It is most often carried on a subcarrier, with radio receivers permanently tuned to a given station in the area, or an HD Radio subchannel of the offering station. Some reading services use alternative methods for reaching their audiences, including broadcasting over SAP, streaming Internet radio, cable TV, or even terrestrial TV.