2009 audi s5 radio mute wire?

I have not had any luck with locating the wire to mute the radio. I believe the wire I'm actually looking for has more to do with the telephone system. I have a Audi OEM bluetooth telephone system and when I receive a phone call it mutes whatever source I'm playing so I can speak on the phone. I need to find this wire so that I can hook up a source to it. I've installed a laser jammer module that has a radio mute wire out of it and it produces voice prompts. If you need any more information about my car let me know. You can reach me at: todd1010 AT gmail DOT com 2009 Audi S5 Bang & Olufsen sound system Audi MMI Navigation

Remove the head unit, one side SHOULD have the terminal layout. P.S. They've stopped using an audio mute pin on a lot of German cars since about 07 with the advent of full system CAN, it's triggered by the factory Bluetooth setting. Alternatively with the unit removed enough to get at the terminals use a DMM to find it. On Porsches it's the trigger wire to the amp AT the amp which we open circuit.

I'm not sure exactly what Audi is or would be calling the head unit on this car. Because the display screen is located up in the center dash, the controls like volume and what not is located down by the center console or gear shifter. The Bang & Olufsen amp is located in the left rear of the trunk and the telephone bluetooth system is located underneath the center armrest. So getting a terminal layout might be a task. I'm working on getting the diagram or pinouts for the telephone system. BTW, when you say "DMM", is that a Digital Multimeter? I'm not much of an electrician but with more help I could probably find and do what you need. I just need more information than you just saying it's the trigger wire to the amp AT the amp which we open circuit. I'm lost at that, LOL! I appreciate your willingness to assist me though, so anything you can do or say is greatly appreciative.

Yes, your are correct with the system being a network but this car's wiring is car MOST bus.

Most simply refers to the plug you are actually looking for! M.O.S.T. = multimedia optimal system transport (I believe) it's a CAN system there will be CAN Hi and Lo wires going to that plug, also if there is one, that's where the mute will be.