INT 15 - OS HOOK - SysRq KEY ACTIVITY (AT,PS)
AH = 85h
AL = 00h SysRq key pressed
= 01h SysRq key released
CF clear
Return: CF clear if successful
AH = 00h
CF set on error
AH = status (see AH=84h)
Notes:  called by keyboard decode routine
the default handler simply returns successfully; programs which wish
to monitor the SysRq key must hook this call

See also: 09

1585 - OS HOOK - SysRq KEY ACTIVITY (AT,PS)