So I bought this smart adapter (http://www.fiio.com.cn/product/index...&MenuID=020303), which is supposed to make iPhone headsets compatible with Android devices.

When I plug in my iphone headset with the adapter attached, the N900 doesn't recognize that there's anything connected. But if I connect my Sony headphones with the adapter attached, disconnect the headphones but leave the adapter in, and then connect the iPhone headset, it works as headphones! Probably cuz it doesn't register the headphones being replaced by the iPhone headset cuz the adapter isn't unplugged.

Also, when I plug in the Nokia headset attached to the adapter, it makes that classic iPhone headset buzz, so it makes me think that the adapter does work.

I also noticed that when I plug the Nokia headset in by itself, dmesg says "input: headset button as /class/input/input5".

Any idea how the N900 checks to see if it's a headphone or headset?