Hey All

I'm looking at ways to use the mute option via the alp Blue mute cable.
However my head unit doesn't have support for mute cable which makes things a little harder.
Having said that I have a amp powering my speakers, plan was to use a relay to turn off remote on power to the amp when the alp alerts.
My question is:
1) Are there any other ways the alp will mute my speakers during a alert?
2) Is it correct that the mute cable provides a ground during a alert?

Thank you for any advice/help