Self-service terminals are becoming more and more the only point of access to many services in todays “self-service society”. They can be found in many areas of everyday life like train stations, universities, bus stops, libraries, movie theaters, airports and banks, with the ATM being the first and still the most commonly used self-service terminal. Unfortunately, ATMs are not very accessible for people with disabilities like blind people, people with cognitive disabilities, the elderly, deaf people and people with motor disabilities. Lack of accessibility is especially problematic with ATMs, because the services of an ATM cannot be accessed through alternative ways like a mobile application. The reason for that is that the user has to be physically present at the ATM and interact with it directly as transaction of money in cash is involved. That makes accessible interaction with ATMs an absolute necessity for users with disabilities. Improving ATM accessibility is difficult for a couple of reasons: There are no universal standards and guidelines for ATM accessibility that manufacturers and developers could rely on. Accessibility needs of individual user groups are well known, e.g. blind people need screen readers and / or braille displays, but ATM hardware is not easily extensible to accommodate these needs. In other words, one cannot simply add hardware and software accessibility tools to an ATM in an effort to make it more accessible. In addition, a feature or a tool that a user with a specific disability needs can be a barrier for another user with a different disability or a user without any disabilities. Trying to implement a lot of accessibility features in one machine would inevitably lead to an over-cluttered UI and bad usability for all users.
This thesis presents an alternative approach for making ATMs more accessible: Decoupling the interaction from the ATM and shifting it as much as possible to the personal accessible environment of the users choice. Parts of the interaction that cannot be decoupled and have to take place at the ATM are executed with a mobile device and a very simple two-step workflow. The solution idea introduces the concept of a digital token that is generated in the personal accessible environment of the user and contains the same information that would result from the traditional interaction with the ATM. This digital token is stored securely on the mobile device of the user and is used later to execute the pre-prepared interaction at the ATM. The resulting experience is less stressful and faster for users with disabilities and requires no changes to the ATM hardware itself. The concrete solution idea and the prototype presented in this thesis are tailored specifically for ATMs, but the general concept - called TokenAccess - could be adapted to any type of self-service terminal.