Thanks again for all the great help and support.

I know I must seem dumb but I have conflicting answers of the following question and I can�t get it straight.
The RCA connections on the HD621 still have me confused.
The 861 is version 4 hardware and the HD621 properties is set to 5.1 (6 channel) output.
I have the IE42 card.
I configured the card to create MD2 using digital inputs D4, D5 and D6

The HD621 has 1/2, 3/4, 5/6, 7/8 digital outputs.

Does 1/2 go to D4?
Does 3/4 go to D5?
What connects up to D6? 5/6 or 7/8?

What is 1/2 - Front Left and Front Right?
What is 3/4 - Center and Sub?
What is 5/6 - Left Side and Right Side?
What is 7/8 - Rear Left and rear Right?

Thanks again everybody and happy holidays.

861v4, HD621, Ultra Classic