Alpine has just released its DPR-RDS1, which allows users to add iPod and iPhone playback to any car stereo with an FM stereo.
At its core, the DPR-RDS1 is essentially an FM modulator hide-away box, which converts a line input into an FM signal. The box is hardwired to the stereo's antenna input to reduce interference from competing FM broadcast signals. FM modulators aren't exactly new tech; my first CD changer was installed using an FM modulator back in the early '90s. However, the DPR-RDS1 differs from your general purpose FM modulator in a few critical ways.
Firstly, it's made for iPod/iPhone; which means that it features a 30-pin dock connector, instead of generic RCA inputs. The dock connector supports 12-volt and 5-volt power, so the DPR-RDS1 will also charge your iPod/iPhone while in use.
The dock connection cable also pulls the currently playing song's metadata and converts it to an Radio Data System (RDS) signal. FM radios that support RDS for displaying text can show the song, artist, and album title on their car stereo's display. OEM car stereo manufacturers haven't exactly been consistent about implementing RDS support into their units--and even less consistent about documenting it when they do--so, double check that your radio supports the protocol before making a purchase.
Because the DPR-RDS1 relies on FM modulation to relay audio data to your car's stereo, you can expect sound quality to be about as good as a strong radio station, which is noticeably lower in quality than CD audio, but still better and more reliable than wireless FM transmitters. Also, FM modulation is a one-way interface and there is no way to control the media player from the headunit, so you'll have to make your song selections from the iPod itself. Try not to spend too much time staring down at your iPod's screen in a moving vehicle.
The DPR-RDS1 Factory Radio Interface for iPod and iPhone is listed at an MSRP of $100 in Alpine's press release and $120 on Alpine's website, so expect to pay something in that range.
Check out the video of the DPR-RDS1 in action after the jump.