Car stereos interfacing with MP3 players
I wrote before on the ideal car dock for an MP3 player but the truth is we could use something even simpler sooner. On my recent trip, we brought the cassette adapter but there was no tape player in the rental car. We forgot the FM transmitter, but that's not as good anyway.
So right away let's see a small headphone plug on the car stereos to do a nice aux input, especially if you are taking away the tape. Duh.
But we can go beyond that with a USB jack, since all music players can plug into that though with different results. A few of them will be clever enough to draw power and recharge from it -- indeed, it is time for cars to have USB jacks just for power since now my cell phones and PDA can all charge from that, and use a cigarette lighter plug with USB jack to do so -- but we want something with the data.
With some music players, plug into USB and they look like a hard drive with music files on it. The stereo could be an MP3 player, but might have trouble with the DRMed music. We could also leave the MP3 player in control, but develop a protocol for it to stream digital audio to the stereo, and for the stereo to send back commands (FF/Rew, Pause, skip track etc.) to the player. Yeah, you could also do this over bluetooth but why wouldn't you want power when in the car, so wires remain the right choice.
Perhaps down the road we might see music players splitting into two halves -- drive and UI electronics/power. The drive unit, be it flash stick or hard disk, holds your music and files, and the UI unit does the rest, and can be mated with any drive, as can the computer and as can the car stereo.