1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 : TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU-!.G13-!#().%G0G0,!.5!%).42/$5#4)/.G0G04/G0G04(%G0G0%84%.$%$G0G0-,they can also be applied to printer-oriented terminals, such as teletypewriters, within the limits imposed bythe facilities available at those
2、 terminals, e.g., information entry through menu selection.By maintaining consistency with Recommendations Z.311-Z.317, these Recommendations facilitate a transitionfrom a man-machine interface using basic syntax and dialogue procedures as described in Section 1 to one based onVDTs.Diagrams and exam
3、ples are used to clarify and illustrate the concepts explained in the text. The diagrams do notinclude exceptional cases and do not specify all possibilities available with the extended MML; those not showndiagrammatically, but which are allowed in the text, are subjects for further study and are no
4、t excluded from theextended MML. Similarly, the examples shown are not intended to imply a particular system implementation.The Recommendations cover aspects of VDTs that users see and use, e.g., data entry, data display, interactivecontrol, user guidance, etc. Specific terminal characteristics are
5、avoided wherever possible.2 Organization of Section 3Section 3 consists of the following Recommendations:Z.321 Introduction to the extended MML for visual display terminalsZ.322 Capabilities of visual display terminalsZ.323 Man-machine interactionRecommendation Z.322 describes many of the capabiliti
6、es currently available in VDTs. Recommendation Z.323focuses on actual man-machine interactions (i.e., how the capabilities are used) by addressing various aspects such asdialogue elements, monologue outputs, user assistance and interactive control.3 Human factors3.1 The human factor view of the man-
7、machine interfaceHuman factor science characterizes the man-machine interface as any part of a system that the user comes incontact with either physically, perceptually or conceptually. The users conceptual model of a system is theknowledge that organizes how the system works and how it can be used
8、to accomplish tasks. The conceptual modelforms an integral part of the user interface.3.2 The need for human factors considerationsThe aim of human factors is to satisfy the largest possible proportion of potential users rather than to tailor thesystem to one user, particularly one with a detailed a
9、nd sophisticated knowledge of the system. Therefore a properman-machine interface takes account of the users needs as well as system requirements. Poor quality will show up as ahigh proportion of input errors, loss of user confidence and motivation and high training costs. A high quality man-machine interface is based on a truly representative user model.Recognized human factors literature has been used in the formulation of Recommendations Z.322 and Z.323.Where appropriate, human factor aspects have been incorporated into the texts.
