In the case of the stairs of a building or a long corridor, the switches that control the same light are pushbuttons, i.e. once pressed they do not maintain their position but return to the starting position.
In this case they are pushbuttons connected to an external relay.
It is possible to replace a conventional pushbutton previously connected to an external relay with iotty or, in general, to connect iotty to an external relay:
After making the connection as shown in the diagram, you will have to configure the type of switch connected to the external relay as ''Pushbutton''.
In this case, as the relay is an external device, you will not be able to view the on/off status of the switch connected to it.