Are you saying you want to:
A) be able to use the scanner as an FD alert meaning it will be quiet except for when specific tones are transmitted
or
B) are you saying that you want to hear all the dialog including the tones that accompany the call dispatch?
I'm guessing B.
If A, please post what agency your are trying to do this with/for.
One of the experts can prob jump in with this info known.