Shunt valve controller Nodemcu

Hello!

Im trying to smartify my shunt valve controller for my wood boiler.

http://www.termoventiler.com/application/files/8914/7325/3307/ECHOME_Manual_v3.0.pdf

This is the manual for the controller, as far as i can understand its working modbus, the creators are not that helpful.

Ive been thinking of connecting nodemcu to the ”rj11?” Connection point where there now sits an antenna with rs485 written on it, supposed to handle radio coms to a thermostat.

Id really appriciate all the help i can get!