OK, sounds like my one, need a picture of the case front, rear, board(s) (incl VSFD as well) and the URL you bought it off. Not all 3163B's are the same there are generic clones which is what I have. Yes the power feed to these boards is 12~30v volts so on the LHS rear is the power in so you dont need to supply 5v to it unless you want to. My board has I think from memory 4 jumpers and not 3 hence its a "generic" clone with no exact manual. I think from memory the jumpers are etched on the pcb?
Ok so its sounds more and more like my setup. My one is single DB25 also and it works fine with Linuxcnc parallel port though the estop doesnt yet work. I bought this aliexpress pci card which works OK.
www.aliexpress.com/item/Great-Q-1Port-I-...-to/32831133280.html
I found a picture of the Chinese under the jumpers (from your build probably) and fed them into an online Chinese OCR program, and got the following, top-to-bottom (JP1-to-JP4?, in any case, JP1 has '5V' in the name, as expected for a '5V selector'):
JP1 "Internal 5V/external isolation"
JP2 "enable On/Off"
JP3 "air-cooling On/Off" (fan?)
JP4 "analog On/Off"
Nice one.... "Fan?" could be the Q is then which are the fan output terminals, that should be fairly easy to test for with an ohmeter and (what voltage comes out) PS cant see any obvious terminals in the pics I have. In my case I just re-wired right off the PSU to 2 new 6025 fans. The existing driver board's fan actually came off the VFD board would you believe! but the VFD itself had no forced cooling, like duh. Wiring was an utter mess and dangerous which I have fixed.
"analoge on/off" vfd speed control? I cant think of anything else.
