I don't run sound, so I bought the DCC ready version and installed the decoder. Didn't want to pay the extra for the sound decoder.
Scaletrains does provide the configuration file for the GP30 to be used on the ESU decoder on their website and I downloaded it, used the ESU program to take a look at it and exported a CV list file that JMRI could use. I imported it, wrote it to the ESU decoder and everything seems to work. What I wanted to do was get the red classification light to come on when I go to shunting mode. From what I saw in the configuration file, AUX10 is where the red lamps are connected, but when I tied AUX10 to F3 (shunting), nothing happened and F5, which cycles the classification lights between white, blue and red, no longer had control of the red.
I explained what I was trying to do to Scaletrains, but that went down a different path for some reason.
From my understanding, AUX port is the term used to identify a wire or solder pad on a decoder. That AUX port is then assigned to a function and can be turned on/off manually or automatically in conjunction with something else. I have a headache...
Thanks for the responses and sorry for getting back late. Am rearranging the room to fit the track layout.