YD/T 5015-2007.Specifications of Engineering Drawing and Graphical Symbols for Communication Project...
YD通讯标准
YD通讯标准
YD通讯标准
YD/T 5015-2015 通信工程制图与图形符号规定
YD/T 5015-2015.Rules and Regulations for Drawing and Graphical Symbols for Communication Engineering...