The VPAP-S is like the S8 and needs a special USB adapter that fits into the card section on the back of the machine. It is ResMed part #22203. The null modem serial adapter will not work for it.

OK. I downloaded ResScan 3.12 from Uncle Bob. Now I need to figure out how to connect my VPAP-S to the computer. I see all of the information about a null modem cable and a USB connector, but I am not clear how and where these attach to the VPAP-S. Or can I just buy the ResMed connector?