If your devices have significantly capacitive or inductive input or output impedances, you’ll also have to keep in mind what frequency you’re operating at.

Professor Hawking used an input device controlled by his cheek movements to choose the words he wanted to use. A special output device turned those words into electronic speech that people could hear.

In prior Java 101 articles, I referred to the concepts of redirection, standard input device, and standard output device. To demonstrate inputting data, several examples called System.in.read().