通光线缆：公司与长飞光纤合资设立的子公司主要从事光纤光缆的研发、生产和销售

Group 1 - The core viewpoint of the article is that Tongguang Cable (300265) has established a joint venture with Yangtze Optical Fibre and Cable (601869) to focus on the research, production, and sales of optical fibers and cables [1] - The joint venture has officially commenced operations with teams from both companies actively engaged in the work [1]