Final answer:
Interfacing two systems means setting them up to communicate and share data or functions, facilitating improved efficiency and expanded capabilities.
Step-by-step explanation:
When two systems are interfaced, it means they are set up to communicate with each other, often to share data or functionalities. This can include a variety of hardware and software configurations such as connecting printers, modems, and external drives (A), storing and retrieving data from a server (B), integrating powerful personal computers (C), and the sharing of data that is needed by both systems (D). A good interface allows separate systems to work together seamlessly, potentially improving efficiency and expanding capabilities.