At 12:45 PM 9/29/97 +0930, you wrote: >The IRQ ack is software based. If you cannot find any examples then I can Get > you some. > >You will need to write: an ISR installer, The ISR its self and an ISR > uninstall. I have an example for MASM its 3 pages long! I might be able to fax > it ok > Thanks for the help. I think I know what you are talking about. I have actually been writing IRQ handlers on the PC for a while, but I thought that there might actually be an additional hardware ack. There is no need to fax the example. Thanks again. Sean Sean Breheny,KA3YXM Electrical Engineering Student