The Three Facets of Usability In Mobile Handsets

Usability has traditionally been a user interface issue that deals with interaction between a system and a user. Mobile handsets are devices that extend the concept of a system to be more than just one device. They are technically complex devices that need a network and services in order to be useful and usable. This paper gives a new perspective to the concept of usability in the context of mobile handsets by using categorisation: user interface, external interface and service interface. We define the technical mobile handset user interface components that are involved in user interaction and are thus forming the usability. We also propose new attributes than can be used to evaluate the usability of a mobile handset: integration of functionality, availability, utility and ease of using services, readiness for use, informativity, usefulness of support material and interoperability.