The term digital section is used in these Recommendations as a general term to include digital line section and digital radio section. This term is defined in Recommendation G.701 (see also Figure 1/G.701 and Figure 2/G.960). Digital sections are defined as component parts of digital links operating at particular bit rates and may be regarded as "black boxes". For digital sections used in digital hierarchy (network) applications the inputs and outputs are recommended in the form of "equipment interfaces" (i.e. in Recommendation G.703 for hierarchical bit rates or in the Recommendation G.931 for non-hierarchical bit rates). For digital sections used for ISDN customer access the "section boundaries" are at the T reference point and the appropriate V reference point. User-network interfaces which may be used at the T reference point are recommended in the I.400 series of Recommendations and the exchange interfaces which may be used at the V reference points are recommended in the Q.500-Series of Recommendations. Digital section Recommendations contain the common network-related requirements applicable to digital radio, metallic and optical transmission systems. The performance requirements relate to network performance objectives.
ITU-T G.901 FRENCH-1988 Referenced Document
ITU-T G.102 TRANSMISSION PERFORMANCE OBJECTIVES AND RECOMMENDATIONS*， 1993-01-01 Update
ITU-T G.901 FRENCH-1988 history
1988ITU-T G.901 FRENCH-1988 GENERAL CONSIDERATIONS ON DIGITAL SECTIONS AND DIGITAL LINE SYSTEMS