ETR 261-4 : 20001

Foreword
Introduction
1 Scope
2 References
3 Definitions, symbols and abbreviations
4 Theoretical Background
   4.1 Usability of Existing Features and Functions
   4.2 Mental models
   4.3 Elderly users
   4.4 Hypothesis, expectations and research questions
5 Two different conceptual models
   5.1 The categories manual
   5.2 The No Categories manual
6 An enhanced minimal phone based interface for ISDN
   supplementary services
   6.1 Design
   6.2 Simulation
   6.3 Differences between the CAT and the NoCAT User
        Interface
7 Method
   7.1 Experimental Task
   7.2 Experimental Design and Independent Variables
   7.3 Data registration
   7.4 Definition of dependent variables
   7.5 Procedure
   7.6 Pilot study
   7.7 Hypothesis
   7.8 Statistical Analyses
8 Results
   8.1 Descriptive statistics with regard to the elderly
   8.2 Effects of different types of transmitted conceptual
        model and effects of practice
   8.3 Types of error
9 Discussion
   9.1 Discussion of the Experimental Method
   9.2 Discussion of Results
10 Conclusions and Recommendations
   10.1 Conclusions
   10.2 Recommendations and Further Study
History

States the results of the research work conducted to develop a European Telecommunication Standard (ETS) defining a harmonized minimum man-machine interface (MMI) for the access and control of public network based telecommunications services, and in particular supplementary services.