Echo from one Modbus hub to another?

[ronkmd]

Hi as I've posted in the Home Assistant Esphome subforum, I'm trying to get one Modbus hub to echo its traffic to another Modbus hub. Basically 2 MAX3485 boards in between a Modbus master and a Modbus slave. I'm really lost at this point. Any help would be appreciated. Thanks. Subforum thread: https://community.home-assistant.io/t/intercept-echo-filter-modbus-communications-from-1-uart-hub-to-another-vs-pool-pump-solar-speed-override-project/340383

[martgras]

That is not possible with the modbus_controller component.
The component can't work as modbus slave.

[ronkmd]

Thanks for the reply. Is it possible otherwise? EspHome is logging each individual byte received, so I'd think there would be some way to extract that and re-send it, right? I thought maybe the UART Text Sensor but I haven't been able to figure out how. I found this (https://www.arduino.cc/en/Tutorial/BuiltInExamples/MultiSerialMega) for Arduino Mega which seems pretty similar but, again, I don't know how to actually implement it in EspHome.