Function 440Ch /4ch     Start Code-Page Prepare                      DOS 3.3+

    Instructs a device driver to begin to prepare a new code-page
    list.

        Entry   AX    = 440Ch
                BX    = Device handle
                CH    = Device category:
                        | 01h   Serial device
                        | 03h   Console (screen)
                        | 05h   Parallel printer
                CL    = 4ch
                DS:DX = Pointer to a CPPrepare structure

        Return  AX = Error code, if CF is set
                     | ??

    ──────────────────────────────────────────────────────────────────

    After calling Start Code-Page Prepare, a program must write data
    defining the codepage fonts to the device driver by using function
    4403h (Send Control Data to Character Device). The code-page data
    is device-specific. The program must end the code-page preparation
    by using function 440Ch /4dh (End Code-Page Prepare).

    A program can instruct the device driver to set up the device with
    the most recently prepared code page by calling Start Code-Page
    Prepare with all code-page numbers set to 0FFFFh. This operation
    must be followed immediately with a call to End Code-Page Prepare.