Electrical connection accessoriesConnection to user selection and ModbusUser selection: Connection to user selection can be used, for instance, for controlling a cooker hood.This happens via a potential free contact in the cooker hood that sends a signal to the unit, which, inturn, increases ventilation when the cooker hood is on. You connect it using pin 4 and 5 in the 8 poleplug of the control panel.User selection can also be used for other functions such as to create imbalance in supply air and extractair ventilation.Modbus: You can communicate with the unit via Modbus, which can be connected in pin 1 (GND), pin 6(A1) and pin 7 (B1) in the 8 pole plug of the control panel.Please, consult user manual for software settings etc.Connect the plug to the unit in point 2: Connecting the user panel.CTS/ComputerConverterModbusUnitUnitPanelPanel18