Home / Standards / GB/T 7342-1987 GB/T 7342-1987 Abolished IEC provisional reference coupler for the calibration of earphones used in audiometry 测听耳机校准用IEC临时参考耦合腔 Standard Type GBT ICS N/A CCS A59 Status Abolished Issue Date 1987-02-28 Implementation 1987-11-01 Centralized Committee 工业和信息化部（电子） Issuing Authority 工业和信息化部（电子）