1     Scope           
 2     References 
 3     Definitions, abbreviations and symbols         
        3.1     Definitions     
        3.2     Abbreviations and acronyms  
        3.3     Symbols          
 4     Overvoltage and overcurrent conditions       
 5     Resistibility requirements   
        5.1     Basic resistibility requirement 
        5.2     Enhanced
resistibility requirement      
        5.3     Special resistibility requirement           
 6     Equipment boundary            
 7     Test conditions        
        7.1     Interface ports             
        7.2     Test types       
        7.3     Test conditions             
        7.4     Test schematics            
 8     Protection coordination       
        8.1     General           
        8.2     Lightning         
        8.3     Power induction, earth potential rise and power contact           
        8.4     Special test protector 
        8.5     Selection of the agreed primary protector        
 9     Acceptance criteria 
10     Tests           
       10.1     External symmetric pair port 
       10.2     External coaxial port 
       10.3     External d.c. and a.c. dedicated power feeding ports  
       10.4     External a.c. mains power port             
       10.5     Internal ports               
Annex A – Test schematics     
        A.1     Introduction  
        A.2     Equipment     
        A.3     Test generators           
        A.4     Waveform generation              
        A.5     Powering, coupling, decoupling and terminations         
        A.6     Test schematics for different types of ports     
Appendix I – Explanations that illustrate test conditions     
        I.1     Testing              
        I.2     Range of lightning and power induction test levels         
        I.3     Relationship between this Recommendation and other product or
product family Recommendations     
Appendix II – Supplementary information for manufacturers and operators     
       II.1     Introduction   
       II.2     Primary protection coordination            
       II.3     MDF voltage at the input of equipment              
       II.4     Current test on mains ports     
       II.5     Earth and neutral potential rise              
       II.6     Special resistibility requirements           
       II.7     Equipment fire in equipment complying with Recommendation ITU‑T K.21         
       II.8     Ethernet          
Bibliography