An ATM system includes a back-end server, an ATM central processing unit (ATM CPU) that receives information relating to the ATM system and a mobile computer. The mobile computer provides a CPU (MC CPU) and a keypad. The mobile computer may also provide a touch screen configured to display an initial ATM display. The ATM system also includes an interface system for interfacing between the ATM CPU and MC CPU. The back-end server formats and transmits to the ATM an API call. The API call requests a location of the user, ATM device information, and identification information of the user. The mobile computer is configured to respond to the API call by providing the location, the ATM device information, and the identification information of the user to the back-end server.