It displays all the info, ie station name, clock-time (if transmitted by your station, not all do) and scrolls the radiotext along the bottom (it's max 64 chars).

AF support auto-retunes to stronger versions of the same station you're listening to as you drive around. Useful in europe where the whole country may be served by one station but on about 20 different frequencies. The tuner software (silently) monitors all the other frequencies in the AF list and will retune to a stronger alternative if available and the current one starts to sound bad.

TA is traffic announce. When listening to another radio station or MP3 (or AUX) the tuner monitors the EON TA flag and will retune to a local radio station when it transmits a traffic announcement - and tune back (or unpause the mp3) when the TA announcement is over. Strange that most commercial radio manages to keep the TA flag transmitted after the traffic report - just long enough for them to capture a bigger audience for their commercials, strangely enough... :)

Hugo