With some additional research, it appears that, at least in the 5G iPod (and likely above), the dock-out signal and the headphone out signal are both fed directly from the CODEC, and the only difference is the dock-out is fixed at 0dB (the same can be achieved from headphone out with volume set to about 90%).

One interesting thing to note is that the Apple Radio Remote and official dock station do interface with a digital output through the same iPod dock-out (different pins). This requires a proprietary Apple chip to authenticate and allow the digital signal to be extracted. Whether or not the Lexus iPod interface kit has the same is anyone's guess.

I just got my IS-F this past weekend and it came from factory with the iPod adapter (glove compartment). I've been using my iPhone through the iPod adapter and at the same time it's connected through bluetooth as phone, so I can still make and receive calls while listening to music.

Well, it's easier to connect the phone from the passenger seat rather than the driver seat, so this morning before I did that as soon as I got to the car, and to my surprise the iPhone started charging right away. I hadn't even started the car, that means that the iPod/iPhone gets charge directly from the battery, not even from the IGNITION ON position. The same thing happens when you switch to radio or CD, or even if you turn the audio off, the iPod/iPhone keeps charging.

?! so that contradicts the OP?

I don't want to change the topic of this thread but how user-friendly is the iPOD adapter? The one on my Xterra is a bit of a PITA to scroll through playlist, artists, songs, etc. and I can't even make it shuffle songs. Is the IS-F adapter controlled through the ML/Navigation screen and voice commands?

Can you order it separately and make it a DIY project? If so, what is the name of the unit or model number, and how much does it cost? That would be better IMO then paying hundreds for the installation.

yes you can get it separately, call up sewell lexus and mention from clublexus for 10% off (something like that). it's diy, just need to take out your nav/radio. installing it shouldn't cost more than 150 imho

Do you happen to know who makes the actual unit? Is it a Toyota/Lexus item, or is it an aftermarket unit like DICE or VAIS?

it's from toyota

Any price? Is this only compatible with certain vehicles? I need to further investigate this.