I have a gizmo attached on serial port and need to detect
changes of controls signals DSR, DTR etc. no data, just
changes (edge). I do it with MSCOMM.ocx and it works,
but only when is CPU on idle and windows messages are
delivered on time. When is load over 20% timing of the
messages sent is broken and can't be decoded properly.
Please let me know with any idea how to tap serial's driver's
IRQ via callback.