After a huge summer break, I'm back to finalize this project.

Next step is to write a simple sketch to be able to communicate with the HVAC. With a wemos D1 mini it's quite easy and with a telnet communication you can follow the communication remotely.

You need the SoftwareSerial library setup to :

	HVACSerial.begin(9600, SWSERIAL_8O1, 13, 14, false);		// baud raute: 9600, data size: 8 bits, parity: odd, stop bits: 1, RX:D7=13, TX:D5=14

 I need some additionnal resistors to dop the serial input from 5V to 3.3V to be compliant with ESP8266.