RIEVTECH STUDIO SOFTWARE MANUAL 4.10.3.1.1 Unused The option “ Unused ” is the default. It means the selected COM port is not used to communicate. 4.10.3.1.2 Connect Device (Master) The option “ Connect Device (Master) ” needs to be selected when the touch screen is as master device. Then you need to set communication parameters for the corresponding PLC. l Manufacturer 444