Since there is no "official" UCOM portal today, the driver is typically hosted on community driver archives. You should look for the "USB Gamepad with Vibration" driver package, which is the standard software for the chipset inside the UC-JS704S2.
Instead, here is a to help you find and install the driver yourself:
For most users, the is sufficient. Only seek a custom driver if: ucom uc js704s2 usb joystick driver win 7 download link
The following sources provide the specific setup files required for the Ucom UC-JS704S2 series, typically identified by filenames like DL807_setup.exe or VL807_setup.exe :
Even with the driver installed, some users run into issues. Here are common problems and solutions: Since there is no "official" UCOM portal today,
Expand or Sound, video and game controllers .
Older UCOM gamepads often fail to communicate properly through blue USB 3.0 ports. Use a black USB 2.0 port instead. Driver Signature Enforcement Error Only seek a custom driver if: The following
Follow these steps to safely install the driver and avoid software conflicts: Step 1: Disconnect the Controller
What are you trying to play with the joystick? Share public link
Unplug the controller, uninstall the driver via Control Panel, restart the PC, reinstall the driver first, and then plug the joystick back in.