Can my GPS attenuate car stereo audio??
 

Hello,
I use a PDA with gps navigation installed in my car. I also have a Sony
CDX-MP40 stereo. The stereo has an ATT lead and the PDA has a stereo
headphone jack. I was wanting to connect the audio from the PDA to my stereo
and somehow incorporate the attenuate function so that my stereo will
attenuate when I receive voive commands from the GPS.

Is this possible to do? Is there a device or adapter that can act as an 'in
between' to activate the attenuate function.

Thank you in advance for your time.

Michael Ripley.