Invisible Indoor Fiber Optical Cable , a revolutionary solution for seamless indoor connectivity. FTTR, or Fiber to the Room, is a networking technology that extends fiber optic connectivity directly into every room of a home or office. With Corning ® Clear Track Fiber Pathways, virtually invisible Gigabit broadband is now available for both inside residences and multidwelling unit (MDU) hallway applications. This article provides an essential guide to understanding indoor invisible cables.