Int F7 Fn 04  - Fsbbs 2.0 - Passdata Buffer                                [-]

   AH = 04h
   AL = function
       00h get PassData buffer contents
       DS:DX -> buffer for PassData contents

       Return: DS:DX buffer filled
       01h set PassData contents
       DS:DX -> buffer containing new PassData
       CH = length of data in buffer

       Return: nothing