Portfolio: Pingtel's voice-over-IP telephone design

Pingtel was designing a new generation of telephones. Their xpressa™ is the world's first Java voice-over-IP phone. They needed someone to design the interactions so they'd be easily understood. You know how hard it can be to transfer a call, and they didn't want that to be a problem for this phone.

An award winning design: "An intuitive interface layout ... the bitmapped LCD panel provides timely information and on-screen help, numerous programmable buttons give users easy access to commands and functions, and clearly marked buttons for 'transfer' and 'conference' make once-difficult functions simple for all users." – Business Week/Industrial Designers Society Gold award, 2002


The xpressa™ (it comes in five colors!)	A close-up of the Palm display

Working on the physical form. Working with the engineers, and industrial and graphic designers, I helped define the layout of the phone itself – the number and placement of buttons, requirements for the screen, use of hard and soft buttons, use of the scrolling knob and more.

Design discovery. I designed the user interface, which involved brainstorming sessions to determine features, usage scenarios to understand them in more detail, a series of paper mockups, usability testing and revisions. This included defining button semantics and syntax, flow of each operation and screen layout. We had complete flow diagrams for each feature, which made design reviews easy.

Prototyping & testing designs. This was the first version of the product, so there was no existing software to build on. We decided on the Palm display with eleven buttons around it. Then we began creating prototypes (read about prototyping). Sketches started out as "wireframes" or schematic designs and got closer and closer to the final form as we iterated, reviewed and tested.

Sample prototypes from different points in xpressa telephone design:

Schematic design example

Version 1: An early sketch for testing. It was focused on interactions, so it was done in black,
white and gray. Color, graphics, typography and layout come later.


Version 2: These were made with a Palm Pilot emulator, and included a little layout and typography.	Version 3: The graphic designer created visual elements for the final prototypes. We used them in a usability study to resolve design questions and to create flow diagrams.

Usability testing. We had to do usability testing long before the physical form or the code was complete. I created paper mockups of all of the major screens and ran the test with an assistant who simulated the phone by swapping the pages as participants said what buttons they would press. They saw a foam model of the phone as a reminder of what it would really look like. This study was very successful. We found problems that would have been more costly to fix later on.

When we started the study, we had two ways to search through the address book stored in the phone. There was no good way to pick one over the other. There was a clear preference for one of them in the usability test, so we picked it.

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