Uncle Bob said:
How do you tell if your system is equipped with it?
One way is to press and hold the 'MIX' button. This should put you into a diagnostic display. Press the mix button several times to cycle through several displays. You should get to one eventually that shows RDS error info.
If you are tuned to a station that broadcasts RDS info, you will see something like: RDS Error rate x% - this tells yu how well the signal is being received and decoded.
When tuned to a station that does not broadcast RDS, it will say something like: RDS no data.
While on this display, you can tune the radio to find different stations, looking for one that does broadcast RDS. (Note that non-zero error rate is okay, you should still see something display, but may miss a character or two. The system was designed to work somewhat with poor signals.)
It's possible that your RDS is working, but there are no stations in your area that broadcast the data. Not all do, and amongst those that do, what they send is completely up to them. In my area, there are a few stations that send the currently playing artist/title (when it's available to them on thier source media). But most stations here just send thier call letters, or sometimes a slogan (e.g., 'classic rock', 'country hits', etc.). Even more stations don't seem to send any RDS at all.