Your machines plug into some switched hub and that hub plugs into the router that you have set up for cable when you use cable and into the router you setup for DSL when you use DSL.
20 to 40 bucks to make this happen.
I work as a medical transcriptionist. I use cable internet primarily and have just ordered DSL to use as a backup. I have Windows XP on a Gateway desktop and wireless HP laptop with a Linksys router WRT54G. I thought it would be as simple as plugging one or the other ethernet cord into the router. Obviously not. Would someone please tell me how to set up the two internets (preferably where the change is made automatically LOL)? I don't care about load sharing, just to use one or the other. Thanks, Georgia