No, that's not what I said. You need to the dongle to use the Bernina embroidery software. You do no need software to use your machine, hence you do not need a dongle. The software is for digitizing and editing. You can do some editing right in your machine, or stitch designs out just as they are when you buy them, no software is needed.
What you do need is a way to send the designs to the machine from your computer. I honestly can't remember how that works on the older machines... if the design you download is an older version of .art (2 or 3 maybe?) you might be able to simply send it over, but your machine won't read the newer versions. I don't know if one of the magic boxes is all that you need, or if you will require Bernina's free artlink software, which I believe you can download on the Bernina website.
You probably need to call a Bernina dealer and ask them what you'll need. My 170 has been gone for 6 or 7 years nows and my memory fails me, I'm sorry!