CONTENTS

 1     Scope 
 2     References 
        2.1     Normative references         
        2.2     Informative references        
 3     Definitions  
 4     Abbreviations   
 5     PCM systems and E1 operation modes    
        5.1     Background from transmission perspective 
        5.2     PCM systems for E1         
        5.3     E1 operation modes           
        5.4     Conclusion for the PCM Frame Spare Bit package
 6     PCM Frame Spare Bit package   
        6.1     Properties  
        6.2     Events    
        6.3     Signals    
        6.4     Statistics 
        6.5     Error code 
        6.6     Procedures
Annex A – Spare bit coding    
        A.1     Sub-multiframe based codeword coding    
        A.2     Single bit coding