Sunday, April 19, 2009

Aspire 4720 Laptop Keyboard

Do you need a new ACER Aspire 4720 Laptop Keyboard for your laptop computer? our company offer all types of Laptop Keyboard for your selection, the ACER Aspire 4720 Laptop Keyboard discount now!
Aspire 4720 series Descirption:
ACER Aspire 4720 series Laptop Keyboard
Layout: US
Letter: English
US standard
Condition: Brand New
Color: White
Remark: Ribbon cable included
SN: 904T907C1D73205A15V300
Weight: 300.00 g
Compatible Partno:MP-07A23U4-442,002-07A23L-A01,PK1301K0200,AEZD1R00110
Fits Models:Aspire 4720 series,Aspire AS4720-4199,Aspire AS4720-4721,Aspire 4720Z
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About Dead key
A dead key or key combination does not generate a character when struck, but modifies the character generated by the key struck immediately after. On some systems, there is no indication to the user that a dead key has been struck, but in some text-entry systems the diacritical mark is displayed along with an indication that the system is waiting for another keystroke: either the base character to be marked, an additional diacritical mark, or space to produce the diacritical mark in isolation.
Many languages use the Latin alphabet and have diacritically-marked letters for which unique keys do not exist on all keyboards. For example, on some keyboard layouts, the acute accent key is a dead key; in this case, striking acute accent then a results in á. Acute accent followed by space results in an acute accent in isolate form.
Most modern old keyboards conform to the ISO 9995 layout. This layout was first defined by the user group at AFNOR in 1984 working under the direction of Alain Souloumiac [1]. Based on this work, a well known ergonomic expert wrote a report (Yves Neuville, Le clavier bureautique et informatique, Cedic-Natan 1985) which was adopted at the ISO Berlin meeting in 1985 and became the reference for the keyboards’ layout.
In Mac OS X, many keyboard layouts employ dead keys. The U.S. Extended layout employs dead keys extensively (reached with option and option-shift) allowing a large inventory of characters to be easily typed. In the U.S. layout, the following smaller selection of dead keys appears.
The user simply types the base character after striking the dead key. For example, the key-strokes option-e and e result in the character é. In Mac OS X, pressing one of these key combinations creates the accent and highlights it, then the final character appears when the key for the base character is pressed. Some diacritically-marked Latin letters, of course, such as ŵ (used in Welsh), cannot be typed with the U.S. layout. That layout, which predates Unicode, provides access only to characters found in the legacy Mac Roman character set and does not support other diacritics, such as ˇ (caron), that are not commonly found in Western European languages (but which are commonly used in many Eastern European languages). However, the Mac OS X U.S. Extended keyboard layout, which was released after Unicode support became common, does provide access to many more diacritics.
The X Window System (used by most Unix-like operating systems, including most Linux distributions) support a Compose key. This dead key allows access to a wide range of extra characters by interpreting the next keystrokes following it. Some keyboards have a key labelled "Compose", but any key can be configured to serve this function.
In AmigaOS dead keys were called "deaf keys" and were generated by the pressing of ALT key. AmigaOS was the first Operating System to use officially an international approved standard ANSI ISO8859-1 layout for all its internal codepage operations and keyboard layout.

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