I'm not suggesting it change the mode, leave the mode what the user set. USB, LSB, DIGI.. Just use the USB input instead of the mic input if the CAT command was used for PTT. I don't know. Maybe it is a silly idea, my Yaesu FT-710 has a menu option to allow me to decide the audio source when CAT does PTT (mic, rear, or USB on the FT-710). It doesn't change the mode, just the audio path.
