It's found by holding the "Info" button down and flashing the parking lights on and off 3 times.
People were telling me that my hands free mode sounded bad....So I bumped my "send volume" up to 5 from 0. That was easy and it did make an improvement. But I want to know about the "Voice Quality" setting. That value is set by the number pad. I just don't have a Service Manual. I'm thinking that my Bluethooth phone might be able to "Tweeked" a little more.