If you’re wanting the built in talkback on the console to send to ME1/500s you just need to assign it on the slink output for the MEs. only downside of the 500 is the limit of 16 inputs. the otherway to send a “talkback” feed from on stage is to do the same but you obviously just have to assign whatever ch input you’ve allocated for an onstage TB and assign it like the first option and then make sure its not assigned to FoH;)