INT 21,44,3 / IOCTL,3 - Write to Character Device

AH = 44h

AL = 03

BX = handle

CX = number of bytes to send

DS:DX = pointer to data buffer

on return

AX = number of bytes written if CF clear

= error code if CF set (see ~DOS ERROR CODES~)

- see bit 14 if IOCTL function 00h to determine if

driver can support IOCTL control strings