The Radio Data System or RDS is a communication standard of the European Broadcasting Union, with which digital information is sent along with a conventional FM radio signal, unnoticeable to the listener.
This RDS signal contains, for example, the name of the station, the frequencies and the type of programme.
And why is that useful? In case of traffic information, an RDS is also sent, which allows to stop the CD player and its related devices for a moment, make the traffic information audible and then switch again.
