hello everyone, i also have tried to connect my Zehnder comfoair 450 to my pi. i have a USB to RS232 adapter and i have modified a console cable as follows: rj45 pin 2 -> rs232 pin 3 rj45 pin 3 -> rs232 pin 2 rj45 pin 8 -> rs232 pin 5 i tried then every script i could find to get it working but i ...

Or just buy this active high board as i did (replaced 3 active low boards, if anyone needs one let me know )

http://www.ebay.com/itm/191294891032

Replace the active low with this one and you don't need to modify, Cut or solder anything