... beginning of 1980s, based in Ningbo, southeastern ChinaExpert in producing optical distribution frames, LAN cabling systems, outdoor equipment cabinet and cable ... % Annually produce 275,000 DDF, 250,000 ODF, 300,000 optical cable splice closures, 150 million loops of MDF, 150,000 ... iron cable trays and 200,000 meters of pigtail trays Digital Distribution Frame (DDF) Unit Module