An ATM system's use case diagram shows how customers interact with it and bank servers communicate with it. For example, customers can deposit cash, check their balances, transfer funds, withdraw cash from ATMs, update PINs, or even make transactions. Thus, each use case depicts a specific function provided by the ATM. The diagram also emphasizes an aspect of the bank server actor which deals with activities such as authenticating users or handling errors during transactions. Relationships like include and extend help to indicate dependence or optionality among the various use cases.
