信呼是一套免费开源的协同办公系统，为各大中小企业通用型在线办公管理系统，精简，便捷方便使用的管理软件，让每个企业单位都有属于自己的办公系统。(Xin Hu is a free open source collaborative office system. It is a streamlined, convenient and convenient management software for all large and medium sized enterprises' general online office management system, so that every business unit has its own office system.)