CONTENTS

 1     Introduction
 2     Structure
 3     Relevant impedances
        3.1     Customer and network equipment
        3.2     Principal impedances
 4     Influence of impedances on principal transmission parameters
        4.1     General
        4.2     Sidetone ratings (STMR and LSTR)
        4.3     Talker echo
        4.4     Stability
        4.5     Listener echo
        4.6     Loss frequency distortion
 5     Outline approach to determining values for key impedances
        5.1     Scope
        5.2     Analogue 2-wire cabling
        5.3     Digital local transmission
        5.4     Analogue/digital interworking situations