27.4 ISDN STANDARDS

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27.4 ISDN STANDARDS

ISDN standards are specified in I series recommendations.

• I.100 series specifies the general concepts. I.110 gives general introduction and structure, I.120 gives overall description of ISDN and evolution, and I.130 gives terminology and concepts to specify services.

• I.200 series specifies service capabilities and services to be provided to the users.

• I.300 series gives the network aspects, including protocol reference model, common channel signaling, numbering, and addressing.

• I.400 series specifies user-network interfaces, including functional grouping and reference points, transmission rates to be offered to users, and protocol specifications at OSI layers 1, 2, and 3.

• I.500 series recommendations specify internetwork interfaces for interworking between ISDN and Public Switched Telephone Network (PSTN), Public Data Network (PDN), Packet Switched Public Data Network (PSPDN), and so on.

• I.600 series recommendations specify maintenance principles to test for failure localization, verification, and so on.

The I series of recommendations of International Tele-communications Union Telecommunications Sector (ITU-T) specifies the ISDN standards.

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