“The product works.
Hardware seems to be of good quality.
Software is slightly better than ebay/Ali Express based Chinese products are having.
It is not very well documented, I could not find firmware upgrade to it and some modes of operation are a bit weird. MQTT is very weakly documented, only through an Alibaba Cloud example.
The product looks like basically a combination of Waveshare's Modbus RTU (serial) relay box and an Ethernet to Serial converter. Note that even it talks about Modbus RTU, there is no serial interface, you can only use Modbus RTU format via TCP. As it supports Modbus/TCP the previous functionality seems a bit redundant.
I wanted to use the MQTT functionality, but it operates again with Modbus/RTU binary format as MQTT payload instead of e.g. expecting JSON tex-based payload and providing responses. Because of that I abandonded the idea and I use it Modbus/TCP mode.”
