According to Kensington, "RDS is now available in most vehicle models offered by leading U.S. and foreign automakers. Our research indicates that over 80 percent of all new cars being sold in the U.S. include RDS-enabled stereos." RDS may soon become mainstream, but in four of the six autos we tried to test the transmitter with, RDS was not even supported. In addition, the $100,000 BMW M6 that car editor Kevin Massy is reviewing supported RDS, but its annoyingly unintuitive iDrive entertainment system failed to display our iPod's track info. We did manage to find a car that worked (Jeep Cherokee) and found the heads-up view of song/track info on our stereo to be quite cool, though more for its gee whiz factor than its usefulness. On several occasions we instinctively tried to press a button on the stereo to change tracks.
With that said, the transmitter itself is a mixed bag. It's in-line style, with the iPod connecting to the end of the cable via a dock connector. It's important to note that this unit will not work with the 3G iPod; furthermore the RDS feature will only work with Nanos and the 5G iPod with video-- the 4G iPod is limited to the FM transmitter. The unit's main piece plugs into a car lighter adapter, as many FM transmitters do. Its odd shape, though, makes it tough to fit it into the tight spaces surrounding your lighter adapter. By twisting the unit, we were able to plug into all of our test cars, but in most cases, we were not able to easily access the power switch. A rare FM transmitter feature, the aim of the switch is to prevent battery drain in some cars, though it won't operate or recharge your iPod unless your car's engine is running (at least not in the cars we tested).
An attractive metallic button, which toggles three ways (left, right, center), is used to choose one of three presets. The presets, which are set by holding down the button, are fairly easy to access. A four-foot cable runs from the base unit and terminates at the 30-pin dock connector for the iPod. This connector has a built-in set of metallic buttons for manual FM tuning. You actually use the iPod's screen to tune, as the dock connector activates software that presumably lives in the dock connector.
You will notice a one- to three-second delay after you plug the connector into the iPod. While it's nice (and uncommon) to use the iPod's display for tuning, it can get in the way of normal navigation. This reviewer prefers a dedicated display. The in-line cable design (it's common, and one advantage is that it offers a low profile) allows passengers to control the iPod, but it can be dangerous for the driver to use while driving. In general, we prefer some kind of dock to sit the iPod in (like DLO's TransPod) for a heads-up view.
The device can be tuned in odd frequencies (88.1, 88.3, 107.9). Sound quality and signal strength rate on the mid-to-high scale; at our most open channel (San Francisco's 88.1), we got good sound reproduction with occasional patches of slight static. In some parts of the city, though, we got a good ounce of static and distortion. You'll get the best results by stretching the cable out. While it wasn't the best we've heard (try the DLO TransPod), it does pass our audio standards. However, twice in one weekend of use we experienced a glitch wherein our iPod froze on the frequency screen. Music continued to play, but we couldn't navigate our iPod until we unplugged the dock connector or powered the unit off.
Overall, the unit's ability to beam iPod metadata to a car stereo is a cool trick, and we were satisfied with the quality of sound. The difficult design of the base unit and the unit's iPod software bugginess should be called out, especially if the iPod screen freeze is a widespread issue. You should also note that the unit has no audio line in for other audio devices, and that you could also either get a transmitter that holds your iPod up (so that it's readable like a car stereo) or find a more expensive integrated solution offered by many automakers.