I seem to have a strange problem. When there is an incoming call, I can't hear the other person and they can't hear me. There is no sound, not even static. It almost seems as though the mic and speakers aren't working at all. However, everything works fine when I make a call from my end. Does anyone know what the problem is? I'm using a 3g iphone.

 

EDIT: I'm using an F900BT.