Function 4403h (68-3)    IOCTL: Write to Character Device

Writes a control string to a character device.

On entry:      AH         44h
AL         03h
BX         Device handle
CX         Number of bytes to write
DS:DX      Data or buffer

Returns:       AX         Error code, if CF is set

Error codes:   1          Device doesn't support control strings

                                                                          

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

See also: 44h
See also: 4402h

4403h (68-3) IOCTL: Write to Character Device