Whew, it's been a while....I haven't been allowed back in the gym due to Covid stuff and now have a smart trainer at home. Let me gather my thoughts to remember.

This is for trainerroad, but should work similar to Zwift:
https://support.trainerroad.com/hc/e...-Cycle-300-400

You had the little "Joule" gps unit that controls the Cycleops. That connected to the Powertap on there via ant+. Then, Zwift could somehow see the Powertap/Cycleops using the Joule GPS as it had bluetooth and I used Zwift on my phone. Then I'd run a little video adapter cable to the TV in the gym.

On the Joule gps unit I would just manually adjust the ERG power command and "pretend" in Zwift.

Some folks got fancy enough to somehow get it to work with either virtual gears or added a real RD to it somehow. I can't find it now. Pretty sure a certain version of all of it could have Zwift give a command to the Cycleops and you used the virtual gears on the Joule gps somehow to change gears.

I never got that far as I didn't own the bike, it was the work gym's.