XAML MVVM: How to make items visilibity grey out based on a bool condition from view model

Question

I'm new for XAML and MVVM. I need to add a control to freeze/greyed out to disable user to click/select buttons/combobox once the device is connected successfully. For below, i need to freeze the combo selection COMPort once connection already been made. I also bind visibiloity once RS485 port type selected. Many thanks in advance :)enter image description here

Here is my code for XAML:

<ComboBox ItemsSource="{Binding Ports}" Visibility="{Binding RS485, Converter={StaticResource BooleanToVisibilityConverter}}" Name="portIdCombo" SelectedItem="{Binding COMPort}" />