The input modules can be built-in or modular. They help the designer given various functions of the standard such as: command device, shutters movement, light control, scene activations.
The built-in input modules are housed in junction boxes and go to collect the state of a push button or voltage-free contact. They can also detect values such as temperature and humidity.
The modular are devices with the same functions as the previous ones, they can be posed in cabinet and have the advantage of being able to collect signals from devices that are also distant tens of meters from them.