Sorry to bump up an old thread, I've recently purchased an N810 WiMAX and a Shure I2c-m headset. The shures work fine on all 3 pin 3.5mm jacks that I've tested on, and the shape of the pin closely matches the standard handsfree that Nokia provides.

My problem is that when I plug in the Shures to the N810, I get a muddied sound due to some overlap in the pins. If I pull out the headphones a bit, it works fine, but its hard to keep it that way. I also tested the mic on the Shures with the N810, and it does not work. Has anyone else seen such a problem? The only difference I've noticed is that the Shure has a pin that's a bit thicker than the other 3.5mm jacks.