Function 440Ch /6ah     Query Selected Code Page                     DOS 3.3+

    Returns the currently selected code page for the specified device.

        Entry   AX    = 440Ch
                BX    = Device handle
                CH    = Device category:
                        | 01h   Serial device
                        | 03h   Console (screen)
                        | 05h   Parallel printer
                CL    = 6ah
                DS:DX = Pointer to a CodePage structure

        Return  CodePage.cpID filled
                or
                AX = Error code, if CF is set
                     | ??