We have several ribbon cable assemblies in our system with very similar numbers.
H0PPS-4006G - H8PPS-4006G - H6PPS-4006G for example.
By comparing these numbers, you can see that one of the options is DIP to DIP while the other two are DIP to DIP reversed. But what does that mean?
Well, in a straight DIP to DIP, H6PP, both ends of the cable with have a connector in the same orientation.
In the DIP to DIP reversed options, the connectors on either side will be in opposite orientations. One upright and one upside-down. The difference between H0PP and H8PP is where position 1 is located.
The below graphic from Assmann helps clear up some of the confusion.