This public link is valid for 7 days and shares a thread, including any personal information you added. This link or copies made by others cannot be deleted. If you share with third parties, their policies apply. Can’t copy the link right now. Try again later.
Windows 10/11 will auto-install a generic driver that treats the card as a PCI device, but it does not create a legacy LPT1 port that old software can see. Your app is looking for an I/O address like 0x378 ; instead, the card is using a memory-mapped range.
However, for true hardware-level LPT emulation, the CH351Q remains the best balance of cost and compatibility—
If you are using a CNC machine, you may need to configure the card to EPP or ECP mode in the Device Manager settings to ensure fast bidirectional communication.
Download the newest updated package from WCH which features updated digital signatures. If you must use an older proprietary driver, temporarily disable Driver Signature Enforcement via the Windows Advanced Startup Options menu to complete installation. Issue 3: Software Cannot Detect the Parallel Port ch351q parallel port driver
If your device is not functioning after installation, check the following:
The CH351Q relies on a software stack that emulates a standard parallel port at the operating system level. Under Windows, the driver creates a virtual LPT port (e.g., LPT3) that user applications can access via CreateFile() or legacy direct I/O after port redirection. Linux support is provided through the parport and ppdev subsystems, often requiring a custom kernel module for full EPP/ECP capability.
You need the . Do not use driver updater tools – they will give you the wrong one.
Technical Report: CH351Q Parallel Port Driver 1. Overview is a high-performance PCI-based I/O controller chipset manufactured by WCH (Nanjing Qinheng Microelectronics) This public link is valid for 7 days
A major challenge when using PCI-based parallel ports like the CH351Q is address mapping. Motherboards historically mapped built-in parallel ports to legacy hardware resources: .
Standard 32-bit PCI bus (compatible with PCI 2.2).
Open Device Manager, locate your parallel port under "Ports (COM & LPT)", right-click it and select "Properties". Go to the "Resources" tab. The I/O range should be listed there. In Linux, you can use the lspci -v command and look for the "I/O ports" entry for the device.
Expand the section. You should see a new entry labeled WCH PCI Parallel Port (LPT1) or similar. Windows 7, XP, and Legacy Systems Can’t copy the link right now
Wait for the success dialogue box ("Driver installation success") to appear, then click OK. Step 3: Verifying Device Manager Installation
A significant advantage of the CH351Q driver set is that it allows the parallel port to be accessed using standard Windows API calls. In modern Windows (NT, 2000, XP, and later), directly accessing hardware I/O ports (using inp / outp functions) is restricted for security reasons. Therefore, the recommended and most reliable method for software developers to communicate with devices connected to the CH351Q's parallel port is to use the CreateFile API function with the port's device name, for example: CreateFile("\\\\.\\LPT2", ... ) . This approach works across all supported Windows versions and avoids the complexities of kernel-level I/O. WCH may also provide a dedicated library for low-level control, but the standard method is the best starting point for robust application development.
As of my last update, the stable version is (or later for Windows 11). The package includes:
If you are having trouble, I can help you find a specific version for Windows 10/11, or walk you through how to configure the LPT port in the Device Manager. CH38XDRV.EXE - Nanjing Qinheng Microelectronics Co., Ltd.
Standard 32-bit PCI bus, conforming to PCI Specification 2.2.