Requirements: Iterate on the previous prototype and perform a final usability test. Make final revisions to your UI based on user feedback and observational data.
UX Test Results: Much of the confusion with starting the device was removed. Overall, the dial approach caused significantly less slips and mistakes, and therefore frustration, on the user's side.
Final Design Commentary: A/B testing would be recommended to decide, once and for all, whether the dial or number pad would be more helpful. A higher fidelity is recommended for a proper test, but this satisfied the needs of the project.