Int 2F/AX=B703h

AX = B703h
ES:DI -> INT 21 handler APPEND should chain to

Return:
ES:DI -> APPEND's INT 21 handler

Note: Each invocation of this function toggles a flag which APPEND uses to determine whether to chain to the user handler or the original INT 21

See Also: AX=B700h - AX=B706h