INT 2A CU - NETWORK - END DOS CRITICAL SECTION                                  
	AH = 81h
	AL = critical section number (00h-0Fh) (see #02555)
Notes:	normally hooked rather than called
	the handler should reawaken any tasks which were suspended due to an
	  attempt to enter the specified critical section
	MS Windows patches the DOS kernel's calls to INT 2A/AH=80h-81h into
	  far calls to its own handler, and does not reflect the calls back
	  to INT 2A unless SYSTEM.INI contains ReflectDOSInt2A=1 or
	  ModifyDOSInt2A=0 in the [386Enh] section
SeeAlso: AH=80h,AH=82h,AX=8700h