CONTENTS

 1     64 kbit/s aggregate
        1.1     General
        1.2     Aggregate bearer channel
        1.3     Frame structure
        1.4     Type of multiplexing
        1.5     Allocation of information bits
        1.6     Telegraph and data channels
        1.7     Frame alignment
        1.8     Loss of telegraph input
        1.9     Bearer interface
       1.10     Telegraph interface
 2     Aggregate bearer rates lower than 64 kbit/s
        2.1     General
        2.2     Aggregate bearer channels
        2.3     Frame structure
        2.4     Type of multiplexing
        2.5     Allocation of information bits
        2.6     Telegraph and data channels
        2.7     Frame alignment
        2.8     Loss of telegraph input
        2.9     Bearer interface
       2.10     Telegraph interface
 3     Compatibility
Annex A – Transition coding process
References