The "mute" function is made to work with different phone interfaces. I currently have a Parrot MKi9200 on my 05 GT with a Shaker 500 to connect my iPhone 4 using bluetoth for the calls or cable for my playlist. When receiving a phone call, I just press the remote button and the shaker 500 is being mute automatically by the Parrot kit and the call is done through the car speakers. When ending the call, mute function is deactivated for radio.
This mute function is mandatory for aftermkatet phone kits going through the original sound car system for calls.
2007 Shelby GT BV5
1989 Fox Convertible GT BV5