Function 4402h (68-2)    IOCTL: Read from Character Device

    Reads a control string from a character device.

       On entry:      AH         44h
                      AL         02h
                      BX         Device handle
                      CX         Number of bytes to read
                      DS:DX      Data or Buffer

       Returns:       AX         Error code, if CF is set

       Error codes:   1          Device doesn't support control strings

  --------------------------------------------------------------------------

    This subfunction reads CX bytes of data from the character device's
    control channel into either DS:DX or memory pointed to by DS:DX.  How
    data is read is defined by the device driver.  Data can be read only
    if the device can process control strings.