I don't remember what pin is used for the phone mute wire. The plug now has no wire in that position. The audio wires go to a unused plug two pins. If I can find any info I will let you know. You will also have to program the radio for phone use. You can download the radio manual from the Becker site. You can email them to get the pin locations. I found them very helpful. Good luck.

http://www.beckerautosound.com/om6806.pdf

info@beckerautosound.com