Radio-controlled/twenty years on

Hi

The Superbowl was a big moment for our band, almost like our Ed Sullivan show, twenty years on. We had to build that stage in six minutes. I was on radio-controlled earphones and microphone. One error and you're off air.

1. Does it say that 20 years earlier that took part in Ed Sulliban show?

2. Does "radio-controlled earphones and microphone" mean that they were wireless, and you might easily lose some kind of connection with the audience if you did something wrong?