*) The problem with no one being able to hear you is not with RN52. It is actually how your phone treats the connection. When your phone is connected to the module, it "gives" all of it's "resources" to it. Or should I say, it "routes" all the signals through it. This includes both: audio out and mic in. And since there's no microphone connected to the module, there's no input. Hence - no one can hear you. I doubt there's a bluetooth profile out there, that allows to route audio out via bluetooth while keeping the mic in on the source level.
*) When switching over to CDC mode, the code sends "SS,0F" (max volume up) to RN52. In case it fails to do it, you can still force "volume up" function on your 9-5 by long pressing CD/RDM button on IHU till you hear a beep (as described
here). That will raise the volume level of RN52 by one.
*) We might think of powering down (or putting the module to sleep) in further revisions of code.
*) The serial speed of RN52 is set to default of 115200bps as it should be. The problem you are seeing is because of buffer sizes and handling of it. I haven't been able to spend much time on that code as have more pressing issues at hand at the moment.
2001 9-5 SE V6; 2006 9-5 Wagon; iOS; BlueSaab version = "latest and greatest" :)