INT 2fH ad81H: Set KEYB.COM Active Code Page

                                                         Compatibility: 5.0+ 
 Expects: AX    ad81H
          BX    Code Page
 Returns: CF    Carry Flag is set if there is an error
          AX    0001H (error code) if the code page is not valid
    Info: This is similar to using the DOS command, Mode CON CP SEL=nnn; it
          activates the specified code page (character set) for the

          As with that Mode command, a code page cannot be selected unless
          the KEYBOARD.SYS device driver has been installed and unless it
          has been previously prepared (Mode CON CP PREP=).

See Also: INT 2fH adxxH: KEYB.COM Functions
          INT 2fH: Multiplex Interrupt
          DOS Functions