If Windows 10 blocks the installation with a Code 52 error, you can temporarily disable driver enforcement. Hold the Shift key while clicking Restart in the Start Menu. Navigate to Troubleshoot > Advanced options > Startup Settings > Restart . Upon reboot, press 7 or F7 to choose "Disable driver signature enforcement," then reinstall the driver.
USB Serial Adapter Drivers (Prolific) - Plugable Technologies
To make the U232-P9 adapter work on Windows 10, you must bypass the generic drivers provided by Windows Update and install a specific compatible version. Step 1: Download the Correct Driver
Click , then click Let me pick from a list of available drivers on my computer .
Ensure the 9-pin connector is securely tightened to your device. u232 p9 driver windows 10
The is a widely used USB-to-Serial (RS-232) adapter cable. It allows modern computers without legacy DB9 serial ports to connect to serial devices. These devices include routers, switches, telescopes, and industrial equipment.
into a USB port. Windows should now automatically associate it with the installed driver Verify in Device Manager: Right-click the button and select Device Manager Expand the Ports (COM & LPT) You should see a new entry, such as "USB to Serial Interface Controller" "Prolific USB-to-Serial Comm Port" Troubleshooting Tips Legacy Hardware:
Windows 10 "Windows Update" may try to overwrite your working driver with the non-functional newer version during the next update cycle.
Do not run the installer yet. First, unplug the U232-P9 adapter from your computer. If Windows 10 blocks the installation with a
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Right-click the downloaded setup file and select .
| Error | Likely Cause | Fix | |-------|--------------|-----| | Code 52 (driver signature) | Windows 10 default driver signing | Use Method 1 (disable signing + legacy driver) | | Code 10 (device won’t start) | Counterfeit Prolific chip with new driver | Uninstall v3.6+ driver, install v3.3.2.102 | | No COM port appears | Missing driver entirely | Install either Prolific legacy or CH340 driver | | Adapter works but disconnects | Power management | Device Manager → USB Root Hub → Properties → Power Management → Uncheck "Allow computer to turn off" | | Baud rate errors | Wrong chip driver | Confirm hardware ID, try alternative driver (CH340 or CP210x) |
: Open Device Manager again. The adapter should now appear under Ports (COM & LPT) as a "USB Serial Port" with an assigned COM number (e.g., COM3). Upon reboot, press 7 or F7 to choose
The U232 P9 is a legacy USB-to-Serial adapter often used to connect industrial equipment, networking hardware, or DIY electronics to modern computers. Because these devices often use older Prolific or proprietary chipsets, getting them to work on Windows 10 can be tricky.
Follow the on-screen prompts and complete the installation wizard.
Common in many budget or older generic adapters. Driver Download Options
You can find recent Windows 10 compatible drivers directly on the MCT Download Page Alternative Package: Some users have success with the USB-RS232 Windows 10 & 11 Driver provided by third-party industrial suppliers. mct.com.tw 2. Manual Installation Steps