DIN EN 61643-21-2013 低压电涌保护装置.第21部分:接到通信和信令网络的电涌保护装置.性能要求和试验方法(IEC 61643-21-2000+2001勘误表+A1-2008,修改采用+A2-2012).德文版本EN 61643-21-2001+A1-2009+A2-2013
Low voltage surge protective devices - Part 21: Surge protective devices connected to telecommunications and signalling networks - Performance requirements and testing methods (IEC 61643-21:2000 + corrigendum 2001 + A1:2008, modified + A2:2012); German ve