Ch351q Parallel Port Driver New! -

Your old software wants 0x378 . The CH351Q is at 0xDFA8 . You have two choices:

The CH351Q requires specific drivers to interface with the operating system. While modern Windows versions may sometimes recognize the chip, dedicated driver packages from WCH-IC ensure full functionality.

For programs like Mach3 or LinuxCNC , the port might appear as an "EPC" or "ECP" port. You may need to manually input the I/O address found in the device resources tab.

The "interesting" part of the CH351Q write-up is the cat-and-mouse game between the silicon manufacturer and OS updates:

Modern versions of Windows (10/11) and Linux have mostly abstracted printer ports away. They treat printers as high-level devices managed by the spooler, not as raw hardware addresses a user program can poke. However, legacy software—like a DOS-based CNC controller or a hobbyist JTAG programmer—expects to write directly to a memory address (e.g., OUT 0x378, AL ).