CH device category: 00H=unknown
03H=console (screen + keyboard) (DOS 3.3+)
05H=parallel printer (DOS 3.2+)
Info: Instructs a device driver to begin preparing a new code-page
list. It can also be used to select the hardware character set
or "refresh" the device with the most recently-prepared character
Notes: To set up a new code page list:
Call fn 4403h (send control data) to pass the code-page
character set remapping information to the driver.
To reset to the hardware code page:
Immediately call fn 440cH 4dH (end cp prepare) without
sending any control data to the driver.
To "refresh" the most recently selected code page:
with -1 (ffffH) and then call this function.
Immediately call fn 440cH 4dH (end cp prepare) without
sending any control data to the driver.
Fn 440cH (generic IOCTL for character devices)