Cardio advice pls

OK so I fulfill my cardio with 30 min (≈3500 steps), twice a day. Now I am in a time crunch and can't dedicate an hour of cardio everyday. I can't run or jog as well as it will attract a lot of unwanted stares. I want to switch to rope jumping (skipping). So anyone experienced, how much time or how many rope jumping should I consider equivalent to a 30 min walking session?