Home / Standards / GB/T 4575-1984 GB/T 4575-1984 Abolished Frequency comparison pilot seriesfor the FDM systems in the toll communication network 长途通信网频分制系统频率比较导频系列 Standard Type GBT ICS 33.040.40 CCS M15 Status 废止 Issue Date 1984-07-17 Implementation 1985-04-01 Responsible Dept 工业和信息化部（通信） Drafting Unit N/A