四会富仕：公司主营业务为PCB的研发生产与销售，部分PCB产品应用于通信领域

Group 1 - The company, Siwei Fushi (300852.SZ), focuses on the research, production, and sales of PCB, with some products applied in the communication field [1] - The company has been asked about its capabilities in high-end optical communication transceiver modules, including research, design, packaging, testing, and sales [3] - There are inquiries regarding the company's ability to provide high-speed optical modules for cloud data center clients and comprehensive solutions for telecom equipment manufacturers in various applications, including 5G transmission [3]