INT 15 - Rational Systems DOS/4GW - ??? AX = BF04h BX = PSP segment of extender Return: nothing??? Notes: if BX is not the PSP segment of the extender, it passes the call down the INT 15 chain; this allows nested instances of the extender grabs INT 2Fh and installs handlers for INT 2F/AX=1605h-1607h SeeAlso: INT 2F/AX=1607h/BX=22C0h