DIGITS from T-Mobile

Program Summary

Develop a communication and collaboration service that helps business and retail customers share and manage multiple phone numbers on a single device.

• Type: Consumer Small Business SaaS
• Market: USA
• Team: 1 Product Manager • 1 Designer • 7 Software Developers
• Role On Feature: Sole Designer as Product Designer, Visual Designer, User Researcher on Web Version
• Timeframe: 5-month Agile rollout • 2022

What Changed

Product shipped, but I left T-Mobile before gaining insight into the results. I did deliver on time and worked with the engineering team to ensure Visual Language, Branding, and Accessibility goals were met.

Who is the Customer?

Understanding the bigger picture

T-Mobile created a virtual phone number app technology as at the time eSim technology wasn't widely available where users can have multiple phone numbers on a single device. To begin I wanted to learn what is the customer motivation around wanting a second or third line and what is the value they place on it.

Some findings from this exploration, Customer's would pay for multiple lines:

The Strategy

Starting With People

How will I improve DIGITS for web/desktop?

I didn't work directly on the original DIGITS mobile product, thus had knowledge gaps about the product. I wanted to make sure we were designing the right solution for desktop/web. I also wanted to give back any discovery to my colleagues working on the mobile solutions. After interviewing with DIGITS mobile design and product about their experience and aligning on testing goals.

My first observational usability study was conducted with 10 users (5 DIGITS users, 5 people new to DIGITS) to understand the customers thought process interacting with the DIGITS mobile apps.

1. Goal 1: How well does the customer understand what DIGITS it and adding a new virtual phone number?
2. Goal 2: How easy are the communication features to use, and what missing features or opportunities can we uncover?

Putting the Plan Together

For my own mental model, I sketched out the features, user workflows, and information architecture by comparing with the DIGITS mobile apps to maintain platform uniformity and onboarding steps.

The Work

Designing the Fix

For brevity on this portfolio writeup, I am only going to focus on a few of the product design solutions for the findings I listed above from the first usability study and product discussions. Contact me if you fancy diving deeper into the full case study.

An example of the calling screen with call logs.

The phone number is displayed by a color that the customer can customize their color preference in settings. The customer can also filter their message and call logs by each of their phone numbers.

One interaction I thought about but discarded was changing the color on the message details screen without needing to go to settings. Discarded due to scope and it might have caused confusion to the customer.

When a user activated a phone number it would be automatically be assigned a unique color. The user could then choose a more meaningful color for that phone number in settings.

I added a Add to call call to action on the call screen. The customer could then dial a number or add an existing contact and add the participants as chips, then select Merge which would merge all the participants into the call in one go. The user would also get feedback if a call failed, or the participant did not answer.

To address the second issue of managing multiple calls on the customers multiple lines, I added the ability to dock the first and second call to multitask and improved the way second and third calls are held and answered.

The user can switch between calls on multiple phone numbers or on the same phone number. This design shows the multi phone number situation where they have received 2 calls, 1 on each phone number.

The last scenario I addressed from a product and design scenario was in the case of three calls. Example: 1 Active call and a second Incoming Call; 1 Active call, a second call on hold, a third incoming call.

While customers were familiar with the feature and icons used in native mobile calling for 1 Active call and 1 incoming call, I needed to consider an elegant solution as the technology allows for 3 call scenario. The solution I tested was to write CTAs that are clear. I also considered localization with this solution, but it was a tradeoff for icons only as usability testing confirmed they were confusing to understand.

Although the technology allowed for more than 3 calls simultaneously I advocated with product's support to stakeholders that we limit the calling feature to a maximum of 3 calls (1 Active, 1 Held, 1 Incoming) for spatial cognitive understanding and safety guardrails.