Is the machine is connected to the PC and then the PC to the internet? I'm guessing the PC is running Windows - what version? Anyway, the first step might be

Is the machine is connected to the PC and then the PC to the internet? I'm guessing the PC is running Windows - what version? Anyway, the first step might be to install WireShark on the PC and look at what sort outgoing message is being sent. And whether anything is coming back from 3M, or just no response. Would you be in the position to place a Linux system with 2 NICs into the connection, so that various forms of spoofing could be attempted? Of course, the biggest problem is that the snooping would have been best done back when the connection to 3M was working and you were able to upload to the PC. Looking at the data plan descriptions, I suspect that the scanned data was transformed by servers hosted by 3M and not by the PC. Of course, that is my guess. At $200 / mth, 3M could be expected to perform some sort of on-going service. BTW the brochure shows the price as $17,000 but you said it cost $30,000. Perhaps you are including the cost of the data plans. As I see it, 3M planned on the machine having an 8 year life. As a business the machine was expected to be amortized 12.5% p.a. with an OPEX of $2400 p.a. Good value considering how much dentists charge.