Hi

>
> Thank you for the information, but I still have one question, how does the
> microprocessor ack the IRQ? I am looking at a diagram of the ISA bus and I
> don't see any IRQ ack pin or anything like that.
>
> Thanks again,
> Sean
>
        The processor does ACK the Interrupt but this goes to the PIC
(Programmable Interrupt Controler) of the PC. The IRQ lines on the ISA
bus connect to the PICs and not directly to the processor. About the
duraction of the pulse I don't have exact numbers at hand, but I think
that the 5us that someone refered (as it hapens with the printer port)
are more than enought.


        best regards

        Jorge F