free download PNG images :Keyboard

In calculation, the computer keyboard is a typewriter type device, which uses the arrangement of buttons or keys to act as mechanical levers or electronic switches. With the decrease of punch card and paper tape, the interaction through teletypewriter keyboard becomes the main input device of computer.

The keyboard usually has characters engraved or printed on the key (button), and each press of the key usually corresponds to a written symbol. However, to generate some symbols, you need to hold down several keys at the same time or in turn. Although most keyboard keys produce letters, numbers, or symbols (characters), other keys, or pressing them at the same time, produce actions or execute computer commands.

Despite the development of alternative input devices, such as mouse, touch screen, pen device, character recognition and speech recognition, keyboard is still the most commonly used device for inputting alphanumeric data directly into computer.

In normal use, the keyboard is used to input text and numbers in the word processor, text editor or other programs. In modern computers, the interpretation of keys is usually determined by software. The computer keyboard distinguishes each physical key and reports all keys to the control software. The keyboard can also be used in computer games. You can use either a regular keyboard or a keyboard with special game functions to speed up commonly used keystroke combinations. The keyboard is also used to issue commands to the computer's operating system, such as the windows control ALT delete combination, which can open a task window or close the computer. Command line interface is a kind of user interface that can complete operation completely through keyboard or another function.