Function 440Ch /65h     Get Iteration Count                          DOS 3.2+

    Returns the number of times the device driver is to try to send
    output to a device before assuming that the device is busy.

        Entry   AX    = 440Ch
                BX    = Device handle
                CH    = Device category:
                        | 01h   Serial device
                        | 03h   Console (screen)
                        | 05h   Parallel printer
                CL    = 65h
                DS:DX = Pointer to 2-byte buffer for iteration count

        Return  Buffer updated
                or
                AX = Error code, if CF is set
                     | 01h Invalid function
                     | 06h Invalid handle
                     |     Device-dependent error