Web485: WebUSB-to-RS485 Board

The Web485 board works as a standard USB-to-RS485 adapter, but with WebUSB support.

The WebUSB JavaScript API allows web-based applications to access USB devices. WebUSB is supported by Chromium-based web browsers (Chrome, Chromium, Edge, Opera). If you are using Google Chrome or another Chromium-based browser, your web pages will be able to access RS485 devices connected to the Web485 board. This even works on Android smartphones!

Tibbo is making extensive use of the WebUSB functionality. The first example of the Web485 board's usefulness is our web-based test application for RS485 Modbus Sensors (Bus Probes). There is also a generic PuTTY-like terminal app called WebTerminal.

To aid in the development of web-based apps (HTML pages) supporting the Web485 board, we offer an easy-to-use WebSerial library.

Key Features

  • Functions as a WebUSB-to-RS485 adapter(1)
  • Baudrates up to 3 Mbps
  • 4-position terminal block:
    • 485+ line (TX+ and RX+ lines tied together)
    • 485- line (TX– and RX– lines tied together)
    • +5V power output(2)
    • Ground
  • Four status LEDs
    • Blue power LED
    • Red TX LED (ON when transmitting)
    • Green RX LED (ON when receiving)
    • Yellow RD/WR LED (ON when transmitting)(3)
  1. WebUSB is supported by Google Chrome and Chromium-based browsers.
  2. The power is provided by the USB port of your PC or Android smartphone. Make sure not to cause an overcurrent condition.
  3. Light pulses emitted by this LED have low brightness and may not be clearly visible.
  • Full-speed (12Mbps) USB2.0 interface on a USB Type-C connector
  • USB-powered, no additional external power necessary
  • Supplied with a USB Type-A-to-C cable
  • Compact, outside dimensions only 57 x 47 x 29 mm
  • Operating system compatibility:

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