0     Introduction          iii
 1     Scope and field of application
 2     References
 3     Definitions
        3.1     Terminology defined in other Recommendations
        3.2     Terminology defined in this Recommendation
        3.3     Graphical conventions
 4     Abbreviations
 5     Networks to be interconnected and data transmission services to be offered
        5.1     Packet Switched Public Data Network (PSPDN)
        5.2     Circuit Switched Public Data Network (CSPDN)
        5.3     Frame Relay Public Data Network (FRPDN)
        5.4     Integrated Services Digital Network (ISDN)
        5.5     Public Switched Telephone Network (PSTN)
        5.6     Common Channel Signalling Network (CCSN)
        5.7     Public mobile systems
        5.8     Private networks
 6     Principles for interworking involving transmission capabilities only
        6.1     Composition and decomposition of subnetworks
        6.2     Categories of interworking
        6.3     Categorization of subnetworks with respect to the support of the OSI-NS
        6.4     Relationships with respect to management
        6.5     Basic principles in relation with service indication parameters
 7     Principles interworking involving both transmission and communication capabilities
        7.1     Composition and decomposition of application relay systems
        7.2     Categories of interworking
        7.3     Identification of application relay system types
        7.4     Relation between application IWF, networks and application relay system types
        7.5     Interconnection of application relay system types
        7.6     Use of application relay system types
        7.7     Relationships with respect to management
        7.8     Relationships with the Reference Model of OSI for ITU-T applications
        7.9     Basic principles in relation with service indication parameters
 8     Description of the different interworking conditions
        8.1     General
        8.2     Interworking via a non-OSI adapter between PSTN and PSPDN
        8.3     Interworking involving ISDN for the provision of datatransmission services
Annex A – Basic categories of subnetworks
        A.1     Type I subnetwork
        A.2     Type II subnetwork
        A.3     Type III subnetwork
        A.4     Type IV subnetwork
Annex B – Examples of subnetwork compositions
        B.1     Examples of Type I and Type II interconnection
        B.2     Type I – Type III interconnection
        B.3     Type II – Type III interconnection
        B.4     Type IV – Type I interconnection