This came from Les Kerr, the developer of MorseKOB, a program for doing landline telegraphy with American Morse.

IF you're using Windows 7 AND you're thinking of upgrading to Windows 10 AND you have a USB-to-serial adapter cable that you'd like to keep using THEN read on...

I have three USB adapter cables. They're made by the same manufacturer, they're the same model number, and they look identical. Two of them work with Windows 10, and one doesn't. But they all work with Windows 7.

These three adapter cables contain a Prolific PL-2303 chip. The two cables that work with Windows 10 have version HXD of the chip, and the one that doesn't has an older HXA chip. It turns out Prolific made the decision not to support their HXA chip in Windows 8 and beyond.

So how can you tell which version of the chip your cable has before taking the leap to Windows 10? Included as part of the Windows driver download package at is a utility program called CheckChipVersion. It runs on Windows 7 and it displays the version number of the cable connected to any given USB port.