I wanted to say thank you to this group for all of the good information about this unit, and to give an update.

I have the Helix DSP Pro, and the information is accurate for the pinout as of this posting.

I'm using a digital potentiometer to control the Helix, and in my findings, 10k just isn't enough. Even at 0 which reads about 9.5k on the multimeter, signal is still passed over the RCA from low to high. In order to get the volume to totally stop I had to have a resistance of 55.7k.

In my findings, the basic steps are 55k, 53k, 37k, 25k and then every ~407 ohms from 25k up to 300 ohms has a noted increase in volume. My source unit only has 64 steps so its possible the increments are even smaller than 407 per step but thats roughly 1db when measured with my SPL meter.

If you use an analog potentiometer this might not be an issue if it goes to a complete circuit disconnect at 0.

I hope this helps someone else. I had to combine a 10k and 50k to get this working.

It would be MIGHTY helpful if anyone knows the DIGITAL control and not the analog one. I cant believe the Director unit is using the analog like the small remote does.