Is it the case that your washer and dryer do not work together, and your heating system does not know what your windows and shutters are doing? Then the interoperability of the systems involved is not ensured.
Interoperability is the ability of various systems to communicate with one another via one interface. To do so, the systems are networked in a way that enables the corresponding signals and information to be exchanged efficiently and in a usable manner. Then, for example, the heating system will know when a window is open and automatically turns off. Or the smart meter can collect, process, and analyze the consumption data for different resources, such as heat, electricity, water, and gas.
In order for the systems to work together, providers and manufacturers will have to have uniform standards. There will also have to be common interfaces in order to connect the applications. This ranges from the standardization of connections and chargers to the adjustment and conversion of electrical voltage and frequencies. Thus, interoperability is a prerequisite for the smart city.