Go back How to Connect Zebra and Printronix Printers via USB: Troubleshooting & Solutions /* by Vishal Gheravada - May 1, 2025 */ Tech Update Setting up USB connections with printers on Windows might seem easy at first, but I encountered several unexpected issues. Recently, I developed an application to connect Zebra and Printronix printers—specifically the Zebra ZD500 and Printronix T820—via USB. Here’s how I approached the problem, what difficulties I faced, and how I overcame them. Starting with Zebra SDK Initially, I thought using Zebra’s official SDK would be the best solution since it directly supports USB connections. I installed Zebra SDK 3.0 in Visual Studio Community Edition 2022 and quickly managed to connect and print barcodes with a Zebra printer. This showed me that using Zebra’s SDK was a reliable choice for standard printing tasks. However, I faced issues when trying to connect to the Printronix T820 printer. Problems with Printronix Compatibility The Printronix T820 printer was set up on another computer using Zebra’s Browser Print software. Unfortunately, this setup identified the printer through drivers rather than as a straightforward USB printer. Zebra’s SDK couldn’t recognize it because it specifically works with printers recognized as USBPRINT devices. Next, I tried using Printronix’s own uniPRT library (version 1.0), but found that it only supported TCP connections, not USB. This meant I had to find another solution. Testing Other Libraries After some research, I discovered wrapper libraries that used libUSB drivers. However, these wrappers didn’t help because libUSB requires devices to use special drivers, whereas our printers used standard Windows drivers like WinUSB. This left me with only one complex option: using Windows native DLL functions to connect directly to USB devices. Working Directly with Native USB Functions Connecting through native Windows functions like usbcomm.dll seemed like a good solution initially. However, due to limited time, implementing these native DLLs was not practical. Instead, I chose a quicker and simpler approach—using symbolic links created from Device Interface GUIDs. To better understand this, I explored the Windows Device Manager and learned how the Windows Registry and device descriptors categorize USB devices (e.g., Generic USB, USB Printer, HID devices). Understanding USB Symbolic Links By examining Zebra’s demo application code, I learned about symbolic links or descriptors. These symbolic links provide essential details like vendor ID, product ID, and serial number required to establish a direct connection. A typical symbolic link looked like this: //?/usb#vid_[VendorID]&pid_[ProductID]#[SerialNumber]#{DeviceInterfaceGUID} //?/usb#vid_0b1f&pid_1e20#90y163510385#{36fc9e60-c465-11cf-8056-444553540000} Initially, I thought the last part of this symbolic link was a class GUID, but further investigation revealed it was actually a Device Interface GUID. Learning About Device Interface GUIDs A Device Interface GUID uniquely identifies types of device interfaces within Windows. These identifiers help connect specific devices, such as printers or mice, with appropriate drivers. Some common GUIDs include: Generic USB Device: {A5DCBF10-6530-11D2-901F-00C04FB951ED} USB Printer: {28D78FAD-5A12-11D1-AE5B-0000F803A8C2} HID Devices: {4D1E55B2-F16F-11CF-88CB-001111000030} USB Host Controller: {3ABF6F2D-71C4-462A-8A92-1E6861E6AF27} USB Hub: {F18A0E88-C30C-11D0-8815-00A0C906BED8} These GUIDs stay the same across all Windows systems, acting as standard identifiers. Successful Connection Once I understood the importance of Device Interface GUIDs, I combined the correct GUID ({28D78FAD-5A12-11D1-AE5B-0000F803A8C2} for USB printers) with the symbolic link. Using Zebra SDK’s USBConnection(symbolicLink) function with this corrected symbolic link allowed me to successfully communicate with the Zebra ZD500 printer. Final Thoughts Connecting printers via USB in Windows involved unexpected complexity, especially due to compatibility and device identification issues. While straightforward methods like Zebra’s SDK worked for some printers, others required deeper technical understanding of USB standards, Windows device management, and native DLL operations. Ultimately, clearly understanding symbolic links and device interface GUIDs helped me establish reliable USB connections for printer applications.
