A friend of mine wrote an open-source feeder for VJoy to enable users of the older non-Plug-and-Play TrioLinker to use it on modern systems. I'm currently able to use a Dreamcast controller on the original TrioLinker (model 403) on Windows 7 X64. I don't know if it will work on other models of Trio Linker or with other controllers, but the functionality is enough for me.
To use the new driver, you must first install vJoy - vjoystick.sourceforge.net/ , run "Configure vJoy" and add a new joystick. Then you download the feeder, plug in the Trio Linker and run it. It will display a command line window, which you can hide if you run the EXE with a "--hide" command line argument. It will stay in memory and quit automatically if you unplug the device. You have to run the feeder every time you plug in the Trio Linker. It must be plugged in before you run the program.
This is very interesting. I've been using the old 0403 trio linker for years with Final Fantasy 11 and a Gamecube controller, however I am stuck with only 32Bit Windows to get it working. If this could finally allow me to use a Gamecube controller on x64 Windows 10 that would make me very happy.
I installed the vJoy app and tried a few of the .exes in the install folder, but I couldn't get it to register any movement from a Gamecube controller. Perhaps only the Dreamcast port of the linker is being monitored? Is it possible to manually select the PS2 or Gamecube port from a config file somewhere?
Actually I re-read the OP and realised I need to run the feeder you are talking about into vJoy. That works great for the Gamecube controller for most buttons, but for some reason the yellow joystick and the Z button don't respond, even after adding 4 PoV and 32 buttons for it to monitor in vJoy. I wonder if I can figure out how to get it past this last hurdle.