hm2_modbus pktuart, probably a firmware request?

I have three machines (lathe, mill, router) that I'd like to update from vfd communication (one GS2, two CommanderSK VFDs). They all work with user mode RS232/RS485 idrivers but I implemented Andy's automatic gear detection on the mill and lathe and the vfd motor speed doesn't update fast enough to track the gear during acclel and decel. 

All three machines are running LCNC 2.9.8.

Lathe uses a 7i96 with 7i95S and a G540 - 7i96p1_7i85dsdi.bit
Mill uses a 7i92 with 7i85S and 7i75 daughtercards, 7i92_7i85sx1sdid.bit 
Router uses a 7i92T with a 7i75 and a G540 7i92t_g540d.bin

I believe the Mill and Lathe are custom built firmware, The router is stock. I don't sse any mention of pktuart in any of the --readhmid files?

My understanding is the 7i96 on the lathe should be RS485 compatible? Hoping this is just a firmware update?
Can I use the Mill's 7i85S RS422 with a RS485 VFD?  Ok if I need to use a TTL/RS485.
Can I use gpio with a TTL/RS485 adapter (solution for Mill and Router).



After intialization, I only need to write 2 registers and read 3 registers and I could block these up. Looks like hm2_modbus would be perfect for what I need if the hardware I have supports it.