CEDIA Expo 2021: Metra AV Features Multi-Viewer Pro With Serial and IP Control September 8, 2021 | Home / September 8, 2021 rave-video / CEDIA Expo 2021: Metra AV Features Multi-Viewer Pro With Serial and IP Control CEDIA Expo 2021: Metra AV Features Multi-Viewer Pro With Serial and IP Control