For Yaesu FT-8x7 transceivers, the most common serial cable used to connect them to a computer for remote control, is CT-62 USB CAT. These cables are not so cheap and can be easily replaced with cables based on CH340 chip, used in the Arduino projects.

Once you have such a replacement cable, connect it in the computer's USB port. It is almost sure that your Windows will not be able to install the proper drivers, so you need to download separately. Access the following link from Windows catalog:

https://www.catalog.update.microsoft.com/Search.aspx?q=CH340

and download the right version, according with your Windows version. Or, you can download them from the chip provider page, for example:

http://www.wch-ic.com/downloads/CH341SER_ZIP.html

After you save the driver files on your computer, open the Device Manager in the Computer Management. Here, the cable is seen as Serial 2.0 USB in "Other devices" category. Select it with a mouse right-click and choose "Update driver". When Windows asks about the the driver source, select "Browse my computer for drivers" then choose the location where you previously save the downloaded drivers. Just continue with the installation and... that's it!