I have an Expert Sleepers FH1 connected to my Digitakt and control all 8 cv outs from 1 MIDI channel of the DT over 5 pin DIN…just sending CCs for automation and LFO, note data is filtered out as that is taken care of by my Beat Step Pro.
But (i did have to edit the scripts, though I’m not sure that is necessary with the FH2 from what I have read).
I purchased an iconnect midi2 to sit in the middle and convert the 5 pin DIN to USB and it works perfectly. The usb out on the DT works plugged in direct, but I wanted that for OB…so I bought the iconnect and it’s flawless.
Pretty sure the OT scenario would be the same over 5 pin DIN… You could try a converter cable as above, but I have had a couple that were useless and gated the midi data…? But that may have been driver related who knows.
Saying that it depends on what you want to achieve. If it is just note data then the A4 could send 4 channels of just pitch and gate straight out from usb. Even the performance knobs can send a value that the FH2 can convert but they have fixed CCs and unlike the OT are not automatable with locks or lfos like you would want. It depends on what you want I guess. And the cv outs could do automation locks anyway???
Fellow Naught uses a DT on a FH1 here…and a simple key step…
He is an octa user and has moved to the FH2, maybe for a beer or patreon donation you could ask him on his YouTube channel?