FrSky Tandem transmitters and the Ethos operating system- RCGroups.com

This RCGroups link contains much information on everything about the FrSky Tandem transmitters and the Ethos operating system. Check out post #2 for a large amount of links to different pieces of information about specific topics.
https://www.rcgroups.com/forums/showthread.php?3703807-FrSky-X20-%28S-HD%29-X20R-%28RS%29-X20-Pro-%28AW%29-Tandem-24-Channels-with-ETHOS