Home / Standards / GB/T 4728.9-1999 GB/T 4728.9-1999 Abolished Graphical symbols for diagrams--Part 9:Telecommunications:Switching and peripheral equipment 电气简图用图形符号 第9部分:电信:交换和外围设备 Standard Type GBT ICS 29.020 CCS K04 Status 废止 Issue Date 1999-03-23 Implementation 1999-10-01 Responsible Dept 国家标准委 Drafting Unit N/A