I've never tried the hands free to be honest, something I've been meaning to do but never got around to. I don't think it has a built in microphone, mine came with an external one which I fitted by tucking the bracket into the join between the drivers side front pillar trim and headlining. I ran the cable along the top of the headlining (I just poked the cable up underneath the front edge) down the passenger pillar and behind the glovebox to the rear of the unit.
