Hardware Reference
In-Depth Information
Note
SeetheTechnicalReferencesectionoftheDVDincludedwiththisbookforacomprehensive
listing of keyboard key numbers and scan codes for both the 101/102-key (Enhanced) key-
board and 104-key Windows keyboard, including HID and hotkey scan codes used on the
latest USB and hotkey keyboards.
Knowing these key number figures and scan codes can be useful when you are troubleshoot-
ing stuck orfailed keys ona keyboard. Diagnostics can report the defective keyswitch bythe
scan code, which varies from keyboard to keyboard as to the character it represents and its
location.
Many keyboards feature hotkeys that either have fixed uses—such as opening the default
web browser, sending the system into standby mode, and adjusting the speaker
volume—or are programmable for user-defined functions. Each of these keys also has
scan codes. USB keyboards use a special series of codes called Human Interface Device
(HID), which are translated into PS/2 scan codes.
International Keyboard Layouts
After the keyboard controller in the system receives the scan codes generated by the key-
board and passes them to the main processor, the OS converts the codes into the appropri-
atealphanumericcharacters.IntheUnitedStates,thesecharactersaretheletters,numbers,
and symbols found on the standard American keyboard.
However,nomatterwhichcharactersyouseeonthekeytops,adjustingthescancodecon-
versionprocesstomapdifferentcharacterstothekeysisrelativelysimple.Windowstakes
advantage of this capability by enabling you to install multiple keyboard layouts to sup-
port various languages, through the Region and Language Options applet in the Windows
Control Panel.
These keyboard layouts map various characters to certain keys on the standard keyboard.
The standard French layout provides easy access to the accented characters commonly
used in that language. For example, pressing the 2 key produces the é character. To type
the numeral 2, you press the Shift+2 key combination. Other French-speaking countries
have different keyboard conventions for the same characters, so Windows includes sup-
port for several keyboard layout variations for some languages, based on nationality.
Note
ItisimportanttounderstandthatthisfeatureisnotthesameasinstallingtheOSinadifferent
language. These keyboard layouts do not modify the text already displayed onscreen; they
only alter the characters generated when you press certain keys.
