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 (as stated in ITU-R Recommendation BS 450-3 and ITU-R Recommendation BS.643-3). The main objectives of RDS are to enable improved functionality for FM receivers and to make them more userfriendly 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, and it is not optional unlike many of the other possible features in RDS.