The manual that has been circulating in 99% the manual for another brand which I'm guessing uses the same control board and the Huanyang. Only the PD function code set is different. In the example in the manual the first data is 00H this should be 03H (PD003).
I've figured out a few more things with the protocol since playing.
When using funciton 03, the data is always 3 bytes (length 03H) and the data is brocken into 1 Byte for the Parameter and two bytes for the Data.
Scott
Oh, and I figured out the font colours. I now have a nice LED green color for the DRO....