Int 2B  - Ibm Rom-dos V4.0 - ???                                           [D]

   AH = function
       00h ??? (modifies data in IBMBIO.COM)
       01h internal operations
       02h ???
       AL = index (00h-0Ch)

       Return: AX = ??? or (CMOS 2Dh and CMOS 2Eh)
       03h get ??? data

       Return: AX = (CMOS 2Dh and CMOS 2Eh)
           BX = FFFFh
       other does nothing

Note:  function 03h is called by ROMSHELL.COM; if BX != 0, then the ES:DI from
     INT 2F/AX=1982h points at valid data

See Also: INT 2F/AX=1982h