1     Functional description of the signalling system
        1.1     General
        1.2     Data User Part
        1.3     Message Transfer Part
 2     General function of data signalling messages, signals, indicators, codes and conditions
        2.1     Signalling messages
        2.2     Service information
        2.3     Signalling information transferred in the signalling messages
        2.4     Data channel signalling condition
 3     Formats and codes
        3.1     Basic format characteristics
        3.2     Label
        3.3     Formats and codes for call and circuit related messages
        3.4     Formats and codes for facility registration and cancellation messages
        3.5     Data channel signalling conditions
 4     Basic call control and signalling procedures
        4.1     General
        4.2     Overall call set-up and clear-down procedures
        4.3     Normal switching procedures
        4.4     Detailed signalling procedures under normal conditions
        4.5     Call handling in abnormal conditions
 5     Additional call control and signalling procedures
        5.1     General

        5.2     Closed user group facilities
        5.3     Bilateral closed user group facilities
        5.4     Calling line identification
        5.5     Called line identification
        5.6     Redirection of calls
        5.7     Connect when free and waiting allowed
        5.8     Reverse charging and reverse charge acceptance
        5.9     Manual answer
       5.10     RPOA selection
       5.11     Network identification utilities
 6     Signalling performance and traffic characteristics in data applications
        6.1     Signalling reliability
        6.2     Message transfer times
        6.3     Data signalling traffic models
Appendix I - Examples of signalling traffic characteristics