Originally Posted by markfsanderson
Nobody has any idea? Wow!
The Futaba FASSTest (telemetry) protocol is in the higher end Futaba systems. Cost more but is proprietary to Futaba (FASST also) with robust error checking of data being transmitter and/or received. T-FHSS has lower manufacturing cost and is similar to other manufacturers FHSS which is somewhat an opensource protocol that anyone can modify for their system.
I currently use Futaba systems of both protocols with no negative issues, primarily because I trust Futaba's signal link to the receiver over any other manufacturer. I have found JR DMSS to be as reliable as Futaba but other radio manufacturer's systems, in my experience, range from fairly reliable to take your chances!
While more costly, all Futaba telemetry sensors work with both protocols.
Depending on your particular use and budget, either Futaba systems works well.