Usability classification example

2 technically different devices

• A voice-interaction device, and a mobile with a built-in visual browser, using WAP.
  • Technically, not in a same device class.

Usability testing

• Consider a task and the speed for its completion.
  • Choosing a hotel from a list.
• If it takes as much time to do it by voice and wap, then in the same device class.