I'm guessing you have a wired in head set and not a blue tooth headset? If so the Nav III does not plug into the bike speaker system thus the wired head set. One of two options: buy the cord to plug phone into voice II system in the little glove box, or get a blue tooth headset and link to phone. I have an iPhone with a scala headset and have it linked to both the Nav III and my head set. When I get a call it still says I need to connect a head set but I can just hit the answer button on my headset and then it will link. Hope this helps