Hardware Reference
In-Depth Information
The alternative keyboard layouts also do not provide support for non-Roman alphabets, such as
Russian and Chinese. The accented characters and other symbols used in languages such as French
and German are part of the standard ASCII character set. They are always accessible to English-
language users through the Windows Character Map utility or through the use of Alt+keypad
combinations. An alternative keyboard layout simply gives you an easier way to access the characters
used in certain languages.
If you work on documents using more than one language, you can install as many keyboard layouts as
necessary and switch between them at will. Using the settings in the Regional and Language Options
applet, you can enable both a selector in the taskbar notification area as well as a key combination
that switches between the installed keyboard layouts.
Keyboard/Mouse Interface Connectors
Keyboards typically have a cable with one of three primary types of connectors at the system end. On
most aftermarket keyboards, the cable is connected inside the keyboard case on the keyboard end,
requiring you to open the keyboard case to disconnect or test it; vendors use different connections,
making cable interchange between brands of keyboards unlikely. When IBM manufactured its own
enhanced keyboards, it used a unique cable assembly that plugged into both the keyboard and the
system unit to make cable replacement or interchange easy. Current IBM keyboards, unfortunately, no
longer use either the shielded data link (SDL) connector inside the keyboard or the telephone cable-
style removable plug-in external keyboard connector used on some more recent models.
Although the method of connecting the keyboard cable to the keyboard can vary (some even use
wireless connections), all PC keyboards use one of the following three connectors to interface the
keyboard (or wireless transceiver) to the computer:
•
5-pin DIN connector
—Used on most obsolete PC systems with Baby-AT form factor
motherboards.
•
6-pin mini-DIN connector
—Often called a PS/2 connector because it was first used on IBM
PS/2 systems.
•
USB connector
—Most recent systems use USB keyboards and mice.
Figure 15.9
and
Table 15.2
show the physical layout and pinouts of the respective keyboard
connector plugs and sockets (except USB); although the 6-pin SDL connector is not used in this form
by most keyboard vendors, most non-IBM keyboards use a somewhat similar connector to attach the
keyboard cable to the inside of the keyboard. You can use the pinouts listed in
Table 15.2
to test the
continuity of each wire in the keyboard connector.
