ORIGINAL: Dick T.
My experiences exactly with the X7S and BNF, not sure why.
Do you mean DX7S? Or is the X7S some other brand of radio?
This is not my first trip around the patch with Spektrum gear nor R/C flying in general. Not bashing Spektrum, just find their operational approach a little clunky. If one begins the hobby with Spektrum products (the whole BNF marketing concept) it's mish-mash of binding plugs, battery voltage, satellite receivers, fluid DMS through DMSX protocols that may or may not be compatible, are learned as the norm.
DMS? Do you mean DSM? The original park-flyer-only protocol? OK, so that was supplanted a few months later with DSM2 and the original DX7, but the DX7 would still support those original AR6000 receivers. The radios we sell today support ALL receiver we ever built with one exception, the original AR6000.
Or are you comparing the compatibility of Spektrum (DSM and DSM2 compatible, DSM2 and DSMX compatible) to another brand? How do you explain then the three current incompatible protocols of other brands out there? Spektrum at least had the good benefit of the customer in mind by providing overlapping compatibility and continuity for over 5 years. Which other company is doing that? Oh wait, they're just barely having their 5-year anniversary, that's right ...
Again, one can appreciate the OP's frustration of finding a new model receiver doesn't work without add ons.
The "add on" comes in the same box, already attached to the base receiver! It's not an add-on, it's a necessary part of the product.
The whole process is certainly foreign to someone's experience with other brands that don't require any of this.
The fact that it is patented just might have something to do with the fact that other companies are not able to provide the same high level of RF redundancy.
Andy