The FT847 with Omnirg PTT and modulation issue might have found a workaround:
In DTR/RTS config Com1 and RTS must be selected, although gray.
In Omnirig RTS-High must be selected (because then a PTT transistor switches on and pulls PTT down).
I had to switch a few times this RTS-Hi to Lo, save, switch back to Hi again and than PTT together with modulation mostly worked.
I must kill Omnirig (Task manager) after varAC because it stays running and stays sitting on Com1.
When there should be time to adress the problem:
The FT847 MUST get PTT (from RTS) and modulation at the same connector.
When PTT comes as a command, then FT847 doesn't know from where to modulate.
Simply: NO PTT command must be sent when using RTS pin.
Sound effects: with only one soundcard the "application sounds" go to the gig modulator (at least my sounds). Strange that I even got PTT with "application sounds" putting these "application sounds" to the antenna instead my ears. Unchecking the use of these sounds stopps that.