2.3 THE PERIPHERALS OF COMPUTERS PERIPHERAL DEVICES Do you know other uses of the word input? And other uses of the word output? The data on the monitor, and any other type of virtual data, are called soft copy, while the printed ones are called hard copy because they are tangible and cannot be modified. buzzer: campanello to display: mostrare microwave oven: forno a microonde pattern: schema Peripheral devices, computer peripherals, or simply peripherals, are any kind of device used to enter information and instructions into a computer for processing and to deliver the output to a human user or to a machine controlled by a computer. They are usually divided into input devices and output devices. Input devices An input device converts incoming data and instructions into a pattern of electrical signals in binary code in order to make them comprehensible to a digital computer. It can send data to another device but cannot receive data from another one. For example, a keyboard and a mouse can send data to the computer, but they cannot receive or reproduce information. Input devices can be: Manual peripherals, which are input devices that allow the user to interact directly with the computer such as in the case of a keyboard, a mouse or a video capturing device; Automated input devices, which use methods of capturing and entering data directly without any human intervention. This mechanism, called direct data entry (DDE), is used when very large amounts of data need to be input quickly and accurately. The most common types of automated devices include sensors and different types of card readers. Output devices An output device translates digitised signals into a form that is understandable to the user. In other words, it reproduces or displays the results of the computer processing. It can receive data from another device, but it cannot send data. For example, a monitor can receive data from the computer, but cannot send information to it. There are: Manual output devices, like a monitor or a printer , and Control devices, which are used to control processes together with sensor input devices. They convert the signals received by the computer into sounds, light, etc., as in the case of a microwave oven which has a buzzer that produces a sound when the food is cooked. Input/output devices There are some devices that can be both input and output (I/O) devices. They can both send and receive data from one device to another. An example of I/O is the touch screen. 72