In IT(information technology) education learners should acquire systematic knowledge about construction schema and fundamental behavior in an IT system. Generally, as for an IT system, it is not so easy to learn those internal principles deeply because they are large and complicated for learners. It would almost be the only method under the present situation to use conventional schematic diagrams to illustrate the principles of IT systems with preparing a set of diagrams. In applying the method, we should consider problems in learning. There is the fear that learners would be confused by the configuration order of schematic diagrams when learned due to their numbers and could not hold the behaviors of an IT system drawn in a schematic diagram.
This paper shows an electronic schematic diagram system(ESD) to solve these problems. This system enables to improve understanding of learners by constructing hierarchical diagrams detailing in a top-down fashion and by presenting actions which make highlight to limit the viewing range within a specific portion in a diagram. A diagram in ESD describes in a specific language with four kinds of description components ; a block, a terminal, connection, and action. ESD can also help to create diagrams by a reuse of schematic diagrams.