HP Vectra Technical Reference Manual page 155

Table 5.5
INT 09H Special Key Sequences
Key
Combinations Action
<CTRL>-<Num lock>
Stops execution until any non-shift key on the
keyboard is struck.
<CTRL>-<Alt>-<
+
>
This key sequence enables the key click feature. The
longer the < CTRL > - < Alt > - <
+
> keys are pressed,
the louder the key click that will result. After maximum
volume is achieved the key click volume will wrap
around to low volume. Applications which depend
upon datacom rates at and above 9600 baud while
keyboard input is being entered should disable the
keyclick feature.
< CTRL> -<Alt> -<->
This key sequence reduces the key click volume until it
is off.
< CTRL> -< Break>
This key combination is interpreted as a program break
request. When this key combination is detected, the
INT 09H driver will execute an INT 1 BH instruction. The
vector for this interrupt is initialized during the boot
process to point to a routine within MS-DOS which
sets a flag then performs an IRET instruction. This
vector may be modified to point to an alternate
routine to handle a < CTRL > - < Break> .
< CTRL> -<Alt> -< DEL> This key combination is interpreted as a system reset
command. When this key combination is detected,
control is transferred to the BIOS Reset routine.
<Shift>-<Prt Sc>
This key combination is interpreted as a print screen
command. When this key combination is detected, an
INT OSH instruction is executed.
<Sys req>
This key is interpreted as a system request for multi-
tasking.
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