Wow, I never realized the system was that complicated. Interesting the article mentions pairing with the positron system.
A few years back someone had abandoned an old Schwinn next to our apartment dumpster and it happened to have both the FFS and Positron. I pumped up the tires and rode it around the block. I wasn't interested in it so I left it where I found it. It was kinda neat to coast and shift.
Oof the article mentions a safety mechanism built into the rear cluster that would allow it to freewheel if the chain gets jammed. Ouch.