Radio Data System (RDS) allows small bits of digital data to be sent together with FM broadcasts. Receivers equipped with RDS technology are called "smart radios" because they can be programmed to filter out programs and receive only broadcasts that fit the scan filter previously programmed by the radio user.
The system allows for configuration of a compatible device to scan specific information that the listener wants to receive. The RDS device bases its filtering mechanism on a preconfigured set of parameters so that the listener doesn't have to manually operate the radio dial. This system is best used in the car, where the driver's attention should be on the road and not on the manipulation of the radio dial.
RDS broadcasts are embedded with specific data, such as station identification, broadcast time and information about the program. These data are sent to RDS-capable receivers, which can process the information and display them according to the customization of the device's user. Other information that may be included in RDS data include alternative frequencies, radio text, traffic announcements and regional programming.
RDS started in Germany and spread to the European Broadcasting Union by 1974. It was later adopted by the United States, in 1992, and was renamed as Radio Broadcast Data System (RBDS).