Low-voltage surge protective devices – Part 22: Surge protective devices connected to telecommunications and signalling networks – Selection and application principles (IEC 61643-22:2015, modified); German version CLC/TS 61643-22:2016
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 06/01/2017

Low-voltage surge protective devices – Part 22: Surge protective devices connected to telecommunications and signalling networks – Selection and application principles (IEC 61643-22:2004, modified); German version CLC/TS 61643-22:2006
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 09/01/2007