07-07-2012, 11:54 AM
KEY BOARD
[attachment=27073]
A keyboard is input device.
A keyboard is a typewriter -style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches. Following the decline of punch cards and paper tape, interaction via teleprinter-style keyboards became the main input device for computers.
Despite the development of alternative input devices, such as the mouse, touchscreen, pen devices, character recognition and voice recognition, the keyboard remains the most commonly used and most versatile device used for direct (human) input into computers.
Standard Keyboard
Standard "full-travel" alphanumeric keyboards have keys that are on three quarter inch centers (0.750 inches, 19.05 mm), and have a key travel of at least 0.150 inches (3.81 mm).
Desktop computer keyboards, such as the 101-key US traditional keyboards or the 104-key Windows keyboards, include alphabetic characters, punctuation symbols, numbers and a variety of function keys.
The internationally common 102/105 key keyboards have a smaller 'left shift' key and an additional key with some more symbols between that and the letter to its right (usually Z or Y).
Also the 'enter' key is usually shaped differently.[1] Computer keyboards are similar to electric-typewriter keyboards but contain additional keys.
Standard USB keyboards can also be connected to some non-desktop devices.
Thumb sized Keyboard
Smaller keyboards have been introduced for laptops (mainly nettops), PDAs, smartphones, or for users who have a limited workspace.
A chorded keyboard allows pressing several keys simultaneously. For example, the GKOS keyboard has been designed for small wireless devices. Other two-handed alternatives more akin to a game controller, such as the AlphaGrip, are also used as a way to input data and text.
A thumb keyboard (thumbboard) is used in some personal digital assistants such as the Palm Treo and BlackBerry and some Ultra-Mobile PCs such as the OQO.
Software Keyboard
Software keyboards or on-screen keyboards often take the form of computer programs that display an image of a keyboard on the screen.
Another input device such as a mouse or a touchscreen can be used to operate each virtual key to enter text.
Software keyboards have become very popular in touchscreen enabled cell phones, due to the additional cost and space requirements of other types of hardware keyboards.
Microsoft Windows, Mac OS X, and some varieties of Linux include on-screen keyboards that can be controlled with the mouse.
[attachment=27073]
A keyboard is input device.
A keyboard is a typewriter -style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches. Following the decline of punch cards and paper tape, interaction via teleprinter-style keyboards became the main input device for computers.
Despite the development of alternative input devices, such as the mouse, touchscreen, pen devices, character recognition and voice recognition, the keyboard remains the most commonly used and most versatile device used for direct (human) input into computers.
Standard Keyboard
Standard "full-travel" alphanumeric keyboards have keys that are on three quarter inch centers (0.750 inches, 19.05 mm), and have a key travel of at least 0.150 inches (3.81 mm).
Desktop computer keyboards, such as the 101-key US traditional keyboards or the 104-key Windows keyboards, include alphabetic characters, punctuation symbols, numbers and a variety of function keys.
The internationally common 102/105 key keyboards have a smaller 'left shift' key and an additional key with some more symbols between that and the letter to its right (usually Z or Y).
Also the 'enter' key is usually shaped differently.[1] Computer keyboards are similar to electric-typewriter keyboards but contain additional keys.
Standard USB keyboards can also be connected to some non-desktop devices.
Thumb sized Keyboard
Smaller keyboards have been introduced for laptops (mainly nettops), PDAs, smartphones, or for users who have a limited workspace.
A chorded keyboard allows pressing several keys simultaneously. For example, the GKOS keyboard has been designed for small wireless devices. Other two-handed alternatives more akin to a game controller, such as the AlphaGrip, are also used as a way to input data and text.
A thumb keyboard (thumbboard) is used in some personal digital assistants such as the Palm Treo and BlackBerry and some Ultra-Mobile PCs such as the OQO.
Software Keyboard
Software keyboards or on-screen keyboards often take the form of computer programs that display an image of a keyboard on the screen.
Another input device such as a mouse or a touchscreen can be used to operate each virtual key to enter text.
Software keyboards have become very popular in touchscreen enabled cell phones, due to the additional cost and space requirements of other types of hardware keyboards.
Microsoft Windows, Mac OS X, and some varieties of Linux include on-screen keyboards that can be controlled with the mouse.