Found a great post by Benjamin which outlines the work he did in finding a driver suitable for the Belkin F5U409 in Windows 64bit systems.

Here’s the blog post he has:  http://www.clearchain.com/blog/posts/how-to-use-a-belkin-f5u409f5u409-cu-usb-to-pda-serial-converter-in-visawindows-7-64bit-mac-osx-10

Download the Driver from MCT:  http://www.mct.com.tw/upload/Driver/U232_10.2.zip

Download the Driver from Benjamin’s server:  http://clearchain.com/downloads/Belkin_FU409/U232_10.2.zip

Download the driver from my local server:  U232_10.2

Windows 10

12/2019

U232-13.2.98.130315 is the driver model I used on Windows 10.

I recently needed to use this old device on my Windows 10 system (Lenovo T470). The driver found here worked with no issues. I have also saved the file to my server if you want to download locally.