If you're encountering a error or cannot find the driver in your Device Manager, I can help you: Identify if you have a counterfeit Prolific chip . Guide you through the manual rollback process . Recommend a modern, reliable replacement converter .
is a USB-to-RS232 (DB9) serial adapter commonly based on the Prolific PL2303
The U232-P9 USB-to-Serial adapter, based on the Prolific PL2303 chipset, is a powerful and versatile tool that continues to be highly useful in professional, industrial, and hobbyist settings. While Windows 10's enhanced security model and Prolific's counterfeit protection measures have created significant compatibility hurdles, these challenges are not insurmountable.
Walk you through the in more detail.
Encountering a "Code 10" error or a yellow exclamation mark next to your "Prolific USB-to-Serial Comm Port" in Device Manager is a common frustration when trying to use an older U232-P9 adapter on Windows 10. This guide explains why this happens and provides proven solutions to get your device working again.
For $15–20, buy an adapter based on:
This almost always means you are using a driver version that is too new for the physical chip inside the cable. Revert to an older version. u232 p9 driver windows 10
If the U232-P9 continues to fail, the hardware itself might be a "clone" or simply too old for modern 64-bit architecture security. Modern alternatives like the or adapters using FTDI chipsets generally offer much better native support for Windows 10 and 11. USB-Serial Adaptor - Microsoft Q&A
When you plug a U232 P9 adapter into a Windows 10 PC (especially versions 1709 and later), you typically experience one of three scenarios:
This is the most common issue with older U232 P9 adapters on Windows 10. It usually means the driver version installed is too new and no longer supports your older hardware revision. If you're encountering a error or cannot find
Locate your USB Serial Device (e.g., "Prolific USB-to-Serial Comm Port"). Right-click on the device and select . Go to the Port Settings tab and click Advanced . Change the COM Port Number to your desired number. Troubleshooting: Still Not Working? If you are still having issues after installing the driver:
To prevent Windows Update from re-downloading a newer driver, you need to change a system policy.
| Chip version | Works on Win10? | |--------------|----------------| | PL2303HXD (Rev D) | ✅ Yes (official driver) | | PL2303TA | ✅ Yes (official driver) | | PL2303HXA (old) | ❌ No (counterfeit detection) | | PL2303RA | ❌ No | | Generic no-name | ❌ No | is a USB-to-RS232 (DB9) serial adapter commonly based
It's worth noting that the MCT USB-RS232 Converter (U232-P9/P25) also has native open-source drivers in the Linux kernel. The Linux driver ( mct_u232 ) is often built directly into the kernel and works without any manual intervention. This guide, however, focuses on the Windows 10 solution.
