1 Nominal LRs of the national systems
    1.1 Definition of nominal LRs of the national systems
    1.2 Recommended values
2 Nominal overall loss of the international chain
3 LRs and directional effects in a complete connection
    3.1 Nominal LRs for each transmission direction
    3.2 Traffic-weighted mean values of OLRs
    3.3 Difference in transmission loss between the two directions of transmission
4 Variation in time and effect of circuit noise
    4.1 Variations in time
    4.2 Effect of circuit noise
5 Practical limits of the OLR between two operators or one operator and one subscriber
6 Incorporation of PCM digital processes in international connections
    6.1 Connections with a digital 4-wire chain extending to the local exchanges
    6.2 Mixed analogue/digital connections
ANNEX A Explanations related to Recommendations G.111, G.121, G.122 G.131, G.134: properties and uses of loudness ratings
A.1 General explanations of loudness rating terms as used in the Series G Recommendations
A.2 Psycho-acoustic model for loudness ratings
A.3 Measurement of loudness ratings of telephone sets
A.4 Application of loudness ratings in the Series G Recommendations
ANNEX B Recommended values and limits of the loudness ratings for circuits in international connections
ANNEX C Translation of LR values into CRE values
ANNEX D Justification for the values of LR appearing in Recommendations G.111 and G.121
D.1 General
D.2 LRs recommended in 1988
D.3 Conclusion