Well, PTT and CAT both work with OmniRig selected for both, but I still don't know why neither would work with CAT selected for Frequency Control and either CAT or DTR/RTS selected for PTT.
Thanks Irad, that was simple enough to fix. Somehow I missed having to select a radio for PTT. I made the selection and now both PTT and CAT works.
As I said in your previous post - when you selected CAT on the PTT configuration side - you did not select anything on the dropdown list. it remained empty.