Just released version 0.2.3 of mbusd - open-source implementation of the Modbus TCP to Modbus RTU (RS-232/485) gateway.


  • Small footprint - suitable to run on embedded devices and SBCs like Raspberry Pi
  • Multi-master - multiple TCP masters can access slave devices in RTU network using same gateway
  • Robustness - can retry requests with mismatched response CRC
  • Flexible RTU modes - speed/parity/stop-bits/timeouts can be configured for RTU network
  • Support for both of automatic and manual (using RTS bit) direction control types for RS-485 transceivers

Supported function codes:

  • 01: Read coil status
  • 02: Read input status
  • 03: Read holding registers
  • 04: Read input registers
  • 05: Force single coil
  • 06: Preset single register
  • 07: Read exception status
  • 15: Force multiple coils
  • 16: Preset multiple registers

Project is distributed under the BSD license. Anyone interested in improving and extending mbusd code could fork project on GitHub. Pull requests are welcome. :)