You should see "Prolific USB-to-Serial Comm Port (COMx)" without a yellow triangle. Alternative Solutions (If 3.3.3.114 Doesn't Work)
| Feature | Prolific 333114 Driver | Prolific Latest Driver (v3.8+) | |--------|------------------------|--------------------------------| | | ✅ Full support | ❌ Deliberately blocked (Code 10) | | Counterfeit Chip Handling | Lenient (works with many clones) | Very strict – disables clones | | Windows 7 Support | ✅ Native | Partial (requires SHA-2 updates) | | Windows 10/11 (latest builds) | Works with signature override | ✅ Fully signed | | Stability with older hardware (PLC, CNC) | Excellent | Unpredictable (timeout errors) | | Driver signing | SHA-1 (older) | SHA-256 (modern) | prolific usbtoserial comm port version 333114 driver
Most budget-friendly USB-to-Serial cables sold online use counterfeit or older Prolific PL2303 chips. Prolific altered their official Windows Update drivers to deliberately reject these older and third-party chips. You should see "Prolific USB-to-Serial Comm Port (COMx)"
The Prolific PL2303 chip family has been manufactured for over two decades. Over that time, the market became flooded with counterfeit or cloned PL2303 chips. The Prolific PL2303 chip family has been manufactured
This specific version is highly sought after by technicians and engineers because it is often the last fully compatible driver for older "knock-off" or generic USB-to-Serial adapters.
Your Device Manager should now show the device working correctly without the yellow exclamation mark. You can now open your terminal software (Putty, TeraTerm, HyperTerminal) and connect to your serial device.