Use the libusb backend. You will need to install libusb-1.0-0-dev and compile the pl340usb kernel module.
Unlike generic USB-to-serial drivers, the Next-340PL driver is highly version-sensitive. Manufacturers often release three distinct branches of this driver: next-340pl driver
If you are having trouble with the cable, you can often fix connection issues by manually selecting an older version Use the libusb backend
git clone https://github.com/opensource-plotter/pl340-driver.git make && sudo make install sudo modprobe pl340usb Manufacturers often release three distinct branches of this
WCH CH340 series / Prolific PL2303 architecture
| Symptom | Likely Cause | Fix | |---------|--------------|-----| | No signal at PLC | Missing termination | Add 120Ω resistor across A+/A- | | Intermittent counts | Loose wiring or noise | Check shielding; use twisted pair cable | | Counts double | Mismatched edge detection | Check PLC input mode (rising/falling edge) | | Overheating | Overvoltage or short circuit | Verify supply voltage; check output wiring | | Only one channel works | Broken driver or cable | Swap A and B at source to test driver |
