Home / Standards / GB/T 14027.4-1992 GB/T 14027.4-1992 Abolished Series and products of communication circuits for semiconductor integrated circuits--Products of dual-tone multi-frequency circuits 半导体集成电路通信电路系列和品种 双音多频电路系列品种 Standard Type GBT ICS 31.200 CCS L56 Status 废止 Issue Date 1992-12-17 Implementation 1993-08-01 Responsible Dept 工业和信息化部（电子） Drafting Unit N/A