Skip to content

CH9329 HID

Hardware Overview

CH9329 is a serial-to-USB HID chip that can emulate keyboard, mouse, or custom HID devices. Depending on configuration, the host recognizes it as a standard USB device.

image-20240812203814747

Usage notes

Based on user feedback, device disconnects could occur. This has been improved by a fix in the snltty submission, which resolves the issue where CH9329 required re-plugging after reboot.

To reduce mouse/keyboard latency:

  • Increase the serial baud rate to 115200

Configuration

Configure CH9329 in one of two ways:

  1. Set environment variables in Docker deployments
  2. Edit /etc/kvmd/override.yaml

Example: 

1
2
3
4
5
6
kvmd:
    hid:
        type: ch9329
        device: /dev/ttyUSB0
        speed: 9600        # Serial baud rate
        read_timeout: 0.3

Performance Tuning

Use the CH9329 configuration & test tool to optimize:

  1. Improve response speed

    • Increase baud rate from 9600 to 115200
    • Update the One-KVM speed setting accordingly

    This improves the remote control experience.

  2. Customize device identity

    • Change USB VID/PID
    • Configure USB string descriptors

CH9329Test_CfgTool