RDS links FM transmitters into a network. An FM transmitter in such a network sends information that gives an RDS radio the following functions:
- Switch automatically to a stronger transmitter if reception in the area is poor.
- Search for programme category, e.g. programme types or traffic information.
- Receive text information on current radio programme.
Some radio stations do not use RDS or only selected parts of its functionality.
When broadcasting news or traffic messages, the radio can switch stations, interrupting the audio source currently in use. The radio returns to the previous audio source and volume when the set programme type is no longer broadcast.