GB/T 16608.51-2012
AbolishedElectromechanical all-or-nothing relays - Part 51: Blank detail specification - Electromechanical all-or-nothing telecom relays of assessed quality - Non-standardized types and construction
有或无机电继电器 第51部分:空白详细规范 电信用有质量评定的有或无机电继电器 非标准类型和结构