http://pastport.jp/user/opticalsintai ja-JP Sintai is specialized in the optical communication field with R&D, production, sales and customer service. https://www.optical-sintai.com/ 2022-04-11T16:35:41+0900 http://pastport.jp/user/opticalsintai/timeline/Guangzhou%20Sintai%20Communication%20Co.%2C%20LTD opticalsintai http://pastport.jp/user/opticalsintai/timeline/Guangzhou%20Sintai%20Communication%20Co.%2C%20LTD