No, this is no question about headset-control

I've a Nokia HS-45 Headset
look here:
http://www.nokia-asia.com/NOKIA_ASIA...54_312x312.jpg

it has more buttons than the old one shipped with my n800.
The old one produces a dbus message but no keycode. The HS-45 doesn't produce any signals. So while headset-control can read from dbus this way cannot be applied to an other headset.

Do you have an idea if there's a way to find out if the HS-45 buttons can be used?

bongo

My N810 came with an HS-48 stereo headset with microphone. It has a single button described as an answer end button. I believe, and may be wrong, it doesn't send a code it only makes or perhaps breaks a connection to power or perhaps ground. Ergo it's funtion is elecrical and not digital.

I know the button on the included headset (HS-48) shunts the mic to ground -- I think the spec was something like 10~1000 Ohm, but I didn't look it up just now. The multi-button ones probably use some sort of serial comm, though I've seen no details, but are definitely known not to work.

If you really want to make that one work, and don't mind wrecking its intended function on other devices, you could probably look up the spec for that shunt, get a soldering iron, and make one of the buttons work; OTOH, if you're content with only one button anyway, you might be better off splicing whatever earbuds you like onto an HS-48.

There actually was a keycode (XF86HeadSet or similar) on OS 2007. Otherwise, it's a D-Bus event.