Introduction

This Recommendation describes how interactions should take place between the user and the system from a logical viewpoint. It describes how an effective man-machine interface should appear to the user when utilizing the capabilities of VDTs as described in Recommendation Z.322. This Recommendation supersedes Recommendations Z.311-Z.317 for interfaces based on VDTs, referencing parts of them where appropriate. Specific human factor guidelines are included within the appropriate divisions of the text.

The capabilities of VDTs, e.g., multiple windows, inverse video, etc., when used consistently can lead to a more effective man-machine interface. Additional dialogue procedures are possible and often preferable with VDTs, e.g., using different windows for different applications. Likewise, the transient nature of information presented on a screen may affect the selection of information display and the manner of presentation. The terminal capabilities available must be considered in conjunction with guidelines presented in this Recommendation in order to produce the most effective interface.

Many advances in the state of the art of man-machine interface design are incorporated in Recommendation Z.323. However, the use of graphics capabilities have not yet been considered in any detail in these Recommendations and must be studied further. The needs of the user moving between different systems or different types of terminals are best facilitated by ensuring that capabilities are used consistently and that user assistance is an integral part of interface design. Interfaces designed according to the principles outlined in this Recommendation will tend to be more user friendly, effective interfaces.