This standard contains the German version of the European Standard EN 61643-312:2013 and is identical with the International Standard IEC 61643-312:2013 + Corrigendum 1:2013. It describes selection and application principles for gas discharge tubes with two or three electrodes. Such devices are used for the protection of applications up to 1 000 V ac or 1 500 V dc in communication or signalling circuits and consist of a gap or series of gaps in an hermetically enclosed discharge medium other than air.