Int 15 Fn 5307  - Advanced Power Management Specification - System Stand-  [p]

   AX = 5307h
   BX = 0001h
   CX = 0001h

Return: CF clear

Notes: puts the entire system into stand-by mode; normally called in response
     to a System Stand-by Request notification after any necessary
     processing, but may also be invoked at the caller's discretion
   should not be called from within a hardware interrupt handler to avoid
     reentrance problems
   the stand-by state is typically exited on an interrupt

See Also: AX=4280h,AX=5307h/BX=0001h/CX=0002h,AX=530Bh