The term “smart home” is misleading, a more accurate term would be “automated home”. Automation allows the type of functionality that is referred to as “smart”.

In essence, a home automation system coordinates the operation of various electronic systems. The typical scenario would be a home with a security system, a lighting control system, and some sort of audio video control system. Usually each of these systems only do their assigned task, either listening to the status of security sensors, turning lights on or off, or sending commands to audio video equipment.

However, with the addition of an automation controller like Crestron, now these separate systems can act in unison. As an example, a Crestron touchscreen or keypad can have a button that is called Away, and when pressing that button the lights can turn off (or on, depending on time of day), all of the TV’s and music systems can turn off, and the security system can arm itself.

In order for the home automation controller to communicate with these various systems, it needs to speak their language, and communicate over some sort of bus, often RS-232 or IP. The “smarts” of a “smart home” come from the ability of an automation controller to communicate with sub-systems, and that requires efficient programming and easy to use and functional user interfaces, which is the hard part.

So in essence, coordination of various sub-systems is what makes a “smart home” smart. It’s really pretty simple.