Overview
The Abacus USB-to-RS232/485 converter uses the Silicon Labs CP210x USB-to-UART bridge chipset. Windows 10 and 11 may install a built-in driver automatically, but for reliable RS-485 operation install the official Silicon Labs driver.
Prerequisites
- Abacus USB-to-RS232/485 converter and USB cable
- Windows 7, 8, 10, or 11
- A utility to extract ZIP files (e.g., 7-Zip or WinRAR)
Download the Correct Driver
| OS | Driver |
|---|---|
| Windows 10 / 11 | CP210x Universal Windows Driver (ZIP) |
| Windows 7 / 8 / 8.1 | CP210x Windows Drivers (ZIP) |
Installation Steps
- Plug the Abacus converter into a USB port.
- Open Device Manager (right-click Start → Device Manager).
- Locate the unknown device with a yellow warning icon — this confirms the driver needs installing.
- Download the correct driver ZIP above and extract it to a local folder.
- Right-click the unknown device → Update Driver.
- Choose Browse my computer for drivers.
- Browse to the extracted folder and click OK.
Windows will install the CP210x driver. The device will reappear as a COM port (e.g., COM3).
Verification
After installation, the device should appear under Ports (COM & LPT) as:
Silicon Labs CP210x USB to UART Bridge (COMx)Note the COM port number — you will need it in your serial communication software or BACnet MS/TP tool.
Troubleshooting
| Symptom | Fix |
|---|---|
| Driver installation fails | Ensure the ZIP was fully extracted before pointing Device Manager to it |
| Device still shows as unknown | Try a different USB port or cable |
| COM port disappears after reboot | Reinstall — ensure the Silicon Labs driver is installed, not the generic Windows serial driver |