I was just reading the manual of my car-kit and I found out why my phone-mute doesn't work on the empeg; from the manual :

so it means in standby, the yellow wire(XCRM) is not grounded and car radio
works normally, but during a call, line is grounded an car radio is muted


the manual suggests a relay of some kind to switch 12V on or off.
Should this be really necessary; isn't there another solution?

The car-kit is a nokia CARK-91

Frank van Gestel