A smart classroom is a teaching space in which conventional facilities are augmented by integrated audio visual and computing equipment, so that a teacher can present material from several sources without leaving the console. Every item in the list is part of that standard arrangement.

Item (i), a smart portion with a touch panel control system, is the control point of the room. From a single touch screen the teacher switches between sources, adjusts volume, dims lights and operates the screen, which is what allows the various devices to work as one system rather than as separate machines.

Item (ii), a PC or laptop connection together with a DVD or VCR player, supplies the content. The computer runs presentations, simulations and internet material, and the player handles recorded video, so the room accommodates both digital and older media.

Item (iii), a document camera with specialised software, allows any physical object - a printed page, a book, a specimen, a piece of student work - to be displayed to the whole class in real time. The specialised software supports annotation, recording and interactive teaching.

Item (iv), a projector and screen, is the output device that makes all of the above visible. Without it nothing the other components produce could be shown to the class, so it is arguably the most basic element of the set.

Since all four items belong to a smart classroom, the code covering all of them applies. Notice that each of the other three codes omits at least one component that is plainly essential - the second, for instance, drops the control system and the document camera while keeping the projector.

Hence a smart classroom has (i), (ii), (iii) and (iv).