Your chip is counterfeit or an old, unsupported version.
If the U232-P9 continues to fail:
| 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) |
Meta Description: Struggling to connect your U232 P9 USB to Serial adapter on Windows 10? This guide covers driver download links, step-by-step installation, error fixes (Code 10, Code 31), and legacy COM port settings. u232 p9 driver windows 10
Use a terminal program like PuTTY or Tera Term:
Loopback test: Short TXD and RXD pins (pins 2 and 3 on DB9). Typing characters should echo back.
This is the most reliable driver for generic U232 P9 adapters on Windows 10 (32-bit and 64-bit). It bypasses the counterfeit detection. Your chip is counterfeit or an old, unsupported version
Step 1 – Download the Driver
Step 2 – Uninstall Existing Driver
Step 3 – Disable Driver Signature Enforcement (Critical) | Error | Likely Cause | Fix |
Step 4 – Install the Legacy Driver
Step 5 – Connect & Test
