This is also know as the interface design. They essentially show how information will be sent into the new system and also how it will show the results of the system. It will not describe how that information is processed nor will it look at the functional requirements other than to show how they are interacted with.

The main elements of input/output design are -

• What the interface looks like
• What each interface element does (which functional requirement does it control?)
• What validation is necessary?