This International Standard describes the Radio Data System@ RDS@ intended for application to VHF/FM sound broadcasts in the range 87@5 MHz to 108@0 MHz which may carry either stereophonic (pilot-tone system) or monophonic programmes ( see clause 2- Normative references ITU-R Recommendations BS 450-3 and BS 643-2). The main objectives of RDS are to enable improved functionality for FM receivers and to make them more user-friendly by using features such as Programme Identification@ Programme Service name display and where applicable@ automatic tuning for portable and car radios@ in particular. The relevant basic tuning and switching information therefore has to be implemented by the type 0 group (see 6.1.5.1)@ and it is not optional unlike many of the other possible features in RDS.