INT 21,44,2 / IOCTL,2 - Read From Character Device
AH = 44h AL = 02 BX = handle CX = number of bytes to read DS:DX = pointer to data buffer on return AX = number of bytes read 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