The effects of device technology on the usability of advanced telephone functions

This paper presents a pilot study that addresses the effect that device technology has on the usability of advanced telephone functions. We prototyped telephone systems using three technologies: the current 12-button phone set, the current phone set augmented with speech synthesis, and a phone set augmented with a display and pointing device. The functions that we offered included call routing, call screening, and message retrieval. Experiments showed that a display-based phone was the fastest to use and was preferred; an interface that used voice-prompting was the slowest and least liked. This points out that future work on prompting interfaces will have to address user control and efficiency issues without causing learning/forgetting problems.