Technical Reference Guide
Compaq Personal Computers
Changed –- March 2000
C-9
C.2.4.2 Multi-Keystroke Functions
Shift - The Shift key (pos. 75/86), when held down, produces a shift state (upper case) for keys
in positions 17-29, 30, 39-51, 60-70, and 76-85 as long as the Caps Lock key (pos. 59) is
toggled off. If the Caps Lock key is toggled on, then a held Shift key produces the lower
(normal) case for the identified pressed keys. The Shift key also reverses the Num Lock state of
key positions 55-57, 72, 74, 88-90, 100, and 101.
Ctrl - The Ctrl keys (pos. 92/96) can be used in conjunction with keys in positions 1-13, 16, 17-
34, 39-54, 60-71, and 76-84. The application determines the actual function. Both Ctrl key
positions provide identical functionality. The pressed combination of Ctrl and Break (pos. 16)
results in the generation of BIOS function INT 1Bh. This software interrupt provides a method of
exiting an application and generally halts execution of the current program.
Alt - The Alt keys (pos. 93/95) can be used in conjunction with the same keys available for use
with the Ctrl keys with the exception that position 14 (SysRq) is available instead of position
16 (Break). The Alt key can also be used in conjunction with the numeric keypad keys (pos. 55-
57, 72-74, and 88-90) to enter the decimal value of an ASCII character code from 1-255. The
application determines the actual function of the keystrokes. Both Alt key positions provide
identical functionality. The combination keystroke of Alt and SysRq results in software
interrupt 15h, AX=8500h being executed. It is up to the application to use or not use this BIOS
function.
The Ctrl and Alt keys can be used together in conjunction with keys in positions 1-13, 17-34, 39-
54, 60-71, and 76-84. The Ctrl and Alt key positions used and the sequence in which they are
pressed make no difference as long as they are held down at the time the third key is pressed. The
Ctrl, Alt, and Delete keystroke combination (required twice if in the Windows environment)
initiates a system reset (warm boot) that i s handled by th e BIOS.
C.2.4.3 Windows Keystrokes
Windows-enhanced keyboards include three additional key positions. Key positions 110 and 111
(marked with the Windows logo ) have the same functionality and are used by themselves
or in combination with other keys to perform specific “hot-key” type functions for the Windows
operating system. The defined functions of the Windows logo keys are listed as follows:
Keystroke Function
Window Logo Open Start menu
Window Logo + F1 Display pop-up menu for the selected object
Window Logo + TAB Activate next task bar button
Window Logo + E E xplore my computer
Window Logo + F Find document
Window Logo + CTRL + F Find computer
Window Logo + M Minimize all
Shift + Window Logo + M Undo minimiz e all
Window Logo + R Display Run dialog box
Window Logo + PAUSE Perform system function
Window Logo + 0-9 Res erved for OEM use (see following text)
The combinati on keystroke of the Window Logo + 1-0 k eys are reserved for OEM use for
auxiliary functions (speaker volume, monitor brightness, password, etc.).
Key position 112 (marked with an application window icon ) is used in combination with
other keys for invoking Windows application functions.