CONTENTS

 Scope of the Recommendation
 1     General characteristics
        1.1     Definitions
        1.2     Abbreviations
        1.3     Application of the equipment
        1.4     Size
        1.5     Modularity
        1.6     Timing signal
 2     Functions
        2.1     Mapping
        2.2     Signal processing
        2.3     Concentration function for switched services
        2.4     Management
 3     Functional representation of the equipment and definition of reference points
        3.1     Functional representation
        3.2     Definition of functional blocks
        3.3     Definition of Reference Points
 4     Tributary interfaces
        4.1     Analogue interfaces
        4.2     Digital interfaces
 5     Aggregate interfaces
        5.1     2048 kbit/s interface
        5.2     8448 kbit/s interface
        5.3     34 368 kbit/s interface
        5.4     139 264 kbit/s interface
 6     Synchronization interface at 2048 kHz
 7     Local control interface
 8     Power interfaces
 9     Defect or failure conditions and consequent actions for the tributary interfaces
        9.1     Defect or failure conditions
        9.2     Consequent actions
10     Defect or failure conditions and consequent actions for the aggregate
       10.1     Defect or failure conditions
       10.2     Consequent actions for defect or failure conditions related to the A Reference Point
       10.3     Consequent actions for defect or failure conditions related to the B2 Reference Point
       10.4     Consequent actions for defect or failure conditions related to the E2/E2˘ Reference Point
11     Defect or failure conditions and consequent actions for the core of the equipment
       11.1     Defect or failure conditions
       11.2     Consequent actions at the O2 or A1 or E1/E˘1 or L2 or N2 Reference Points
12     Performance monitoring
13     Performance of the equipment
       13.1     Jitter
       13.2     Transfer delay
       13.3     Slips
       13.4     Service availability
       13.5     Error performance
       13.6     Bit sequence independence
14     Management
Appendix I  –  Baseband line transmission system
        I.1     General
        I.2     Physical model of the line transmission system
        I.3     Functional description of the DCE
        I.4     Functions of TU functional block
        I.5     Requirements for a line transmission system using 2B1Q line code
        I.6     DCE Management channel
        I.7     Management System Unit