If you look in the folder C:\Program Files (x86)\Aerosoft\PFE\pfe_displayer\ you will see a file called "pfe_displayer.exe" if you run this when PFE is connected to the sim you will see a nice application that shows you what communication options are available to you on the currently tuned radio frequency. Also in the lower right corner you will see some buttons labelled "Dept Freqs" "Dest Freqs" if you click and hold these button with the mouse you will see the frequencies you will be using during your flight.