Rec. ITU-T K.21 Amendment 1 (06/2020) Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrentsAmendment 1 Summary History FOREWORD Table of Contents Amendment 1 1 Scope 2 References 3 Definitions 3.1 Terms defined elsewhere 3.2 Terms defined in this Recommendation 4 Abbreviations and acronyms 4.1 Symbols 5 Conventions 6 Tests Annex A Special resistibility requirements A.1 Introduction A.2 Special resistibility requirements Bibliography