652D FRP flat ADSS fiber optic cable, featuring 6 cores and spans from 200m to 1000m for aerial communication networks. 2 Loose tube (LT) & filler rod (FR) color code “LT” means “loose tube”;“FR” means “filler rod” 4. Cable Assembly & Dimensions Max. It provides reliable single-mode data transmission without metallic support, ideal for power distribution networks, telecommunication lines. The structure of ADSS (single-sheath stranded type) is to place 250um optical fiber into a loose tube made of PBT, which is then filled with waterproof compound. A steel wire, sometimes sheathed with polyethylene (PE) for cable with high fiber count, locates in the center of the core as. No fiber break and no sheath damage. Tubes and fillers are stranded around the strength member into a circular.