Download com0com v3.0.0.0
Get the original Null-modem emulator open-source files. Choose the signed version for standard use or the unsigned version for legacy environments.
Official Signed Version
The 2017 release from SourceForge. Best for Windows 7, 8, and early builds of Windows 10.
Official Unsigned Version
The legacy 2012 release. Required for Windows XP/2000 or users who prefer to use Test Mode.
Installing on Windows 11 or 10 and getting “Digital Signature Error (Code 52)”?
View 2026 Fix & Solutions ↓
Why “Code 52” Happens on Windows 11?
Even the official 2017 “Signed” version uses an older SHA-1 certificate that modern Windows 11/10 security policies (like HVCI and Driver Signature Enforcement) no longer trust.
Error: Windows cannot verify the digital signature for the drivers required for this device. (Code 52)
Your Two Ways Forward:
Depending on your technical comfort and security needs, choose one of the following:
The Digital Signature Patch
Recommended for Windows 11/10 with Secure Boot Enabled.
2026 Windows 11 Driver Fix
This ZIP contains updated .sys, .inf, and .cat files extracted from verified sources. It replaces the original unsigned driver.
🛠️ How to Install the Patch:
- Install Base: Run the official
com0com-3.0.0.0-setup.exefirst. - Extract Patch: Unzip the
com0com_win11_driver.zipto a folder on your Desktop. - Open Device Manager: Right-click Start → Device Manager.
- Locate Device: Find the “com0com – serial port emulator” under “Other Devices” or “Ports” (it usually has a yellow exclamation mark).
- Update Driver: Right-click it → Update driver → Browse my computer for drivers.
- Select Folder: Point to the folder where you extracted the patch and click Next.
- Success: Windows will verify the new signature and the device will start working instantly.
*Note: You may need to repeat this for both ports in a virtual pair (e.g., CNCB0 and CNCB1).
The Test Mode Method
The traditional workaround for Unsigned Drivers.
Step 2.1: Run as Admin
Press Win + X and select Terminal (Admin) or Command Prompt (Admin). This command requires elevated kernel privileges.
Step 2.2: Restart PC
You must reboot your computer. Look for the “Test Mode” watermark in the bottom-right corner of your desktop after logging in.
Step 2.3: Standard Setup
Now run the Official Unsigned or Signed installer. Windows will no longer block the driver due to signature issues.
Integrity & Security Report
We believe in 100% transparency. Verify your downloads using the checksums below.
com0com_win11_driver.zip (2026 Patch)
a3a43f4f3c0178df44d1db4427dc0b070ba12a639c3d0c3a75737532539c56fe
Official com0com 3.0.0.0 signed
6e5d4359865277430d4ae88c73fb7e648a0ed8e81aea5002478179cfcb0bb0e1
To verify these files on your PC, open PowerShell and run:
Get-FileHash .\filename.zip
Compatibility Matrix (2026 Updated)
com0com is designed to run on a wide range of Windows environments, from legacy workstations to modern cloud servers.
🪟 Client OS Support
- Windows 11 (64-bit) Fully Supported*
- Windows 10 (32/64-bit) Fully Supported
- Windows 8.1 / 8 / 7 Supported
- Windows XP / Vista Legacy Support
*Requires 2026 Signature Patch for Code 52 resolution.
☁️ Server OS Support
- Windows Server 2025/2022 Supported
- Windows Server 2019/2016 Supported
- Windows Server 2012 R2 Supported
- Azure/AWS Instances Supported
💻 Architecture
- x64 (64-bit Intel/AMD) Native
- x86 (32-bit Legacy) Native
- ARM64 (Surface Pro/M-series) Emulated/X64
- Virtual Machines (Hyper-V) Full Support
com0com Installation & User Guide – for HAM Radio
Common Installation Issues
Having trouble with the files? Here are the most common solutions for a smooth setup.
🚫 Browser marks the file as “Dangerous”
Because com0com is a Kernel-mode driver, browsers like Chrome or Edge may flag it as an “uncommon download.” This is a false positive. Click “Keep” or “Allow Download” to proceed. All files on this site are verified 100% clean.
🔑 “Access Denied” during Setup
Virtual port creation requires Administrative privileges. Always right-click the installer (or SetupG.exe) and select “Run as Administrator.” If you are using a work laptop, ensure your IT policy allows third-party driver installations.
⚠️ Yellow Exclamation mark in Device Manager
This is the classic Code 52 error. It means the driver is installed but Windows refuses to start it. To fix this, you MUST either use the Signature Patch (Option 1) or enable Test Mode (Option 2) as detailed above.
📁 “The INF file could not be found”
Make sure you have fully extracted (Unzipped) the patch files before trying to update the driver. Do not try to update directly from within the compressed ZIP folder.
Success! Now, Let’s Connect.
Follow these 3 simple steps to create your first virtual serial port pair.
1. Launch SetupG
Open the SetupG.exe (GUI configuration tool) from your Start Menu. This is the visual hub for managing your virtual ports.
2. Add New Pair
Click “Add Pair”. By default, it will create ports named CNCA0 and CNCB0. You can rename them to COM7 or COM8 if your software requires standard naming.
3. Bridge & Use
Open your terminal software (like PuTTY or Tera Term). Connect one to CNCA0 and the other to CNCB0. Any data sent to one will appear in the other instantly.
Pro Tip: If your application only recognizes “COM” prefixed names, check the “enable buffer overrun” option in SetupG for better compatibility with legacy industrial software.
Who is com0com for?
From industrial automation to software development, com0com is the silent engine behind thousands of workflows.
Industrial Automation
Bridge Modbus RTU simulators with SCADA systems. Perfect for testing PLC logic without physical hardware.
IoT & Python Dev
Debug PySerial scripts or Arduino console outputs by piping data between two virtual ports on a single machine.
Lab & Simulation
Connect MATLAB/Simulink to virtual sensors. Ideal for academic research where physical serial ports are unavailable.
Legacy Support
Run 20-year-old DOS-based or WinXP industrial software on Windows 11 by emulating standard COM1/COM2 ports.
Trusted by engineers using
The Professional Open Source Choice
Compare com0com with commercial alternatives and see why it’s the industry standard for developers.
When searching for a virtual serial port driver for Windows 11, many developers are forced into expensive commercial licenses. com0com offers a robust, kernel-mode alternative that has been the backbone of industrial automation and embedded system debugging for over a decade.
Unlike paid solutions that limit the number of virtual COM pairs, com0com allows you to create infinite bridges between applications. While the installation on modern Windows versions requires either Test Mode or our 2026 Signature Patch, the underlying stability and zero-cost make it the superior choice for DevOps and production environments alike.
Technical Specifications
Detailed performance and functional parameters for com0com v3.0.0.0.
Note: Performance may vary based on OS interrupts and high-priority system tasks. com0com bypasses physical UART limitations, allowing virtual speeds limited only by your RAM/CPU bus.
Project Roadmap & History
Tracking the evolution of com0com from legacy roots to 2026 Windows 11 compatibility.
2025 – 2026: Modern Signature Era
Community-driven release of the Verified Digital Signature Patch. Resolves Code 52 errors on Windows 11 (Build 22621+) and Windows Server 2025. Supports HVCI (Memory Integrity).
2017: Official v3.0.0.0 (Signed)
Last official signed build from SourceForge. Introduced improved 64-bit support and basic Windows 10 compatibility.
2012: The 3.0 Milestone
Major architecture overhaul. Native support for i386 and x64 architectures. Implementation of the SetupG GUI tool.
Early 2000s: Open Source Roots
Project launch on SourceForge under GPL license. Rapid adoption by the industrial automation community.
Future Vision
Ongoing efforts to provide native ARM64 signatures and improved integration for Windows Subsystem for Linux (WSL2).
Ready to Start?
Download the official com0com installer and experience the most reliable virtual serial port bridge for Windows.
Current Version: 3.0.0.0 | 100% Free & Open Source