I've posted in the past about the convention I use for WWII-era ATC.
Basically, it really comes down to what
YOU expect to hear.
The convention I use for "ETO" aircraft is the side or fuse letters and numbers.
To use my ATC stuff, you'll want to include the "atc_id", "atc_airline", and "atc_flight_number" lines in each aircraft's "[fltsim.XX]" section of the aircraft.cfg file.
As an example, let's say we want ATC to talk to aircraft XJ825.
We would add the following to that aircraft's "fltsim.XX" section:
atc_id=XJ825
atc_airline=XJ
atc_flight_number=XJ825
In the game, we would see the text of "XJ825" if its enabled and the aircraft would be called "X-Ray Julliet Eight Two Five".
So, what's going on and how can you tweak this stuff for FS9?
The "atc_id=" is only for the red text if you have it enabled.
The "atc_airline=" is actually a dummy and is needed if you want to hear both letters and numbers. If FS9 can't decode the letters in this section, it just skips it after a very short delay.
The "atc_flight_number=" line can contain letters
and numbers
as long as we use the dummy line above it. If we don't use the dummy line, weird things can happen.
As for the rest, you would add
atc_type=HAWKER
atc_model=HURRICANE
or
atc_type=SUPERMARINE
atc_model=SPITFIRE
to the [general] section just below the "[fltsim.XX]" sections.
Note that this convention only uses stock FS9 voice files and we don't have to worry about running Edit Voicepack.