I have a Kenwood head unit and it came with a wire for a telephone mute but since there is no wire from the truck for this I am not able to take advantage of it. I have seen it on pioneer head units as well. Has anyone been able to hook this up?

 

It's for use with a cell phone handsfree kit. I have a unit that when a call comes into my cell phone sends a signal to this wire. When this happens the kenwood unit says call and mutes all the sound automatically. If you're not going to use it just tape the end off and let it be.