<p>Touch-tone interfaces are today widely used in help-centers and support services. Studies have shown that interfaces like these have many limitations and are therefore hard to design. MVAS is a voicemail interface using touch- tone input for navigation. Today, shortcomings in the interface limit the users’ ability to use the functionality in a satisfying way. This thesis describes a mainly qualitative study which evaluates and tests the interface of MVAS to come up with how the interface should be designed to be easier to use. The results show that the usability of MVAS is poor but the functionality of the same is both impressive and appreciated. The suggested redesign of the system, based on the identified usability problems, considers both the interaction model used in the interface as well as the conformity to the set of heuristics used in the evaluation. The proposed redesign keeps all the functionality in the system intact and also makes the functionality more explicit through improving the usability. A more explicit structure will facilitate usage of a larger portion of the functionality. However, the limitation of the key-pad affects the redesign so the most favorable design is unreachable. If the interaction model is changed or furthered developed to allow speech input the limitations experienced with the current redesign will diminish and a higher degree of usability can be reached.</p>

Touch-tone interfaces are today widely used in help-centers and support services. Studies have shown that interfaces like these have many limitations and are therefore hard to design. MVAS is a voicemail interface using touch- tone input for navigation. Today, shortcomings in the interface limit the users’ ability to use the functionality in a satisfying way. This thesis describes a mainly qualitative study which evaluates and tests the interface of MVAS to come up with how the interface should be designed to be easier to use. The results show that the usability of MVAS is poor but the functionality of the same is both impressive and appreciated. The suggested redesign of the system, based on the identified usability problems, considers both the interaction model used in the interface as well as the conformity to the set of heuristics used in the evaluation. The proposed redesign keeps all the functionality in the system intact and also makes the functionality more explicit through improving the usability. A more explicit structure will facilitate usage of a larger portion of the functionality. However, the limitation of the key-pad affects the redesign so the most favorable design is unreachable. If the interaction model is changed or furthered developed to allow speech input the limitations experienced with the current redesign will diminish and a higher degree of usability can be reached.