Hello. My name is Michael. I can help you with your question.
We are not Apple Corporate - you have reached JustAnswer - an independent paid support provider. But helping people with this sort of thing is what we do. I'll certainly listen to whatever you have to say. Primarily, I would need to know what you are trying to connect to with the dialup modem (for example is it just a dialup internet connection?) and the version of your Mac OSX operating system.
Jerry, do you have another connection to the internet on one of those computers? For remote support?