I have just bought a headset wh 701 and it doesn't work on my n900. When I connect headset to n900 the relative icon doesn't appear on the screen and I hear the music only from phone's speaker and not from headset. How can I fix this? I have tried headset on another phone and on iMAC and in this case headset works well. Why this type of headset doesn't work on n900? thanks a lot in advance for your help

I would normally point you to the wiki page but it's down

However IIRC WH-701 are not compatible.

I use WH-205.

thanks a lot for the quick reply. I have used WH 205 in the past and now I have bought 701 because on the nokia store they say that this type of headset is compatible with n900...but it doesn't seem true

There are olny a couple of headset that work due to the TV out feature on the N900. They also don't have multiple control buttons.

So if you need buttons look at the bluetooth headsets/controllers

Like BH-214

It's not due to tvout. It's due to some phones having different pinout on heasphone port. There is a standard for this, and everyone before apple were following the standard, and after apple almost only nokia follows standard...

Sadly with the Lumia series even Nokia have gone the apple way by supporting it...

Yes Apple have a different pinout.

We are talking about controlling the device with multiple buttons on the headset. This is not available on the N900 as I said.
The single button on the headsets compatible for N900 like WH-205 works by shorting Mic/TV-out pin to ground IIRC.

Whereas WH-701 sends signals from the controller up the "Mic Pin", the N900 hardware cannot process this.