https://www.syu.ac.kr/blog/video-chat-%eb%a9%98%ed%86%a0%eb%a7%81-%ec%b0%b8%ec%97%ac%ec%9e%90-%eb%aa%a8%ec%a7%91_%ec%99%b8%ea%b5%ad%ea%b3%84-%ec%84%b8%ec%9d%bc%ec%a6%88%eb%94%94%ec%a6%88%eb%8b%88%ec%82%ac/%ec%9e%87%eb%8b%a4-video-chat-%ec%98%81%ec%83%81-%eb%a9%98%ed%86%a0%eb%a7%81-%ec%86%8c%ea%b0%9c%ed%8e%98%ec%9d%b4%ec%a7%80-%ec%98%88%ec%8b%9c-pdf_page_2/