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Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification

superseded recommendation/international standard from the International Telecommunication Union
CreativeWork itu_t_recommendation_version Q26985444
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Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification

Summary

Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification is an ITU-T recommendation version[1].

Key Facts

  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's instance of is recorded as ISDN user-network interface - Data link layer specification — instance of (P31): ITU-T recommendation version[2].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's publisher is recorded as ISDN user-network interface - Data link layer specification — publisher (P123): ITU Telecommunication Standardization Sector[3].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's edition number is recorded as 11/1988[4].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's language of work or name is recorded as ISDN user-network interface - Data link layer specification — language of work or name (P407): English[5].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's publication date is recorded as +1988-11-25T00:00:00Z[6].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's official website is recorded as http://www.itu.int/rec/T-REC-Q.921-198811-S/en[7].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's work available at URL is recorded as https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-Q.921-198811-S!!PDF-E&type=items[8].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's number of pages is recorded as {'unit': '1', 'amount': '+118'}[9].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's standards body is recorded as ISDN user-network interface - Data link layer specification — standards body (P1462): International Telecommunication Union[10].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's title is recorded as ISDN user-network interface - Data link layer specification[11].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's cites work is recorded as ISDN user-network interface - Data link layer specification — cites work (P2860): Recommendation I.430 (11/1988): Basic user-network interface - Layer 1 specification[12].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's cites work is recorded as ISDN user-network interface - Data link layer specification — cites work (P2860): Recommendation I.431 (11/1988): Primary rate user-network interface - Layer 1 specification[13].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's cites work is recorded as ISDN user-network interface - Data link layer specification — cites work (P2860): Recommendation Q.920 (11/1988): ISDN user-network interface data link layer - General aspects[14].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's cites work is recorded as ISDN user-network interface - Data link layer specification — cites work (P2860): Recommendation Q.930 (11/1988): ISDN user-network interface layer 3 - General aspects[15].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's cites work is recorded as ISDN user-network interface - Data link layer specification — cites work (P2860): Recommendation Q.931 (11/1988): ISDN user-network interface layer 3 specification for basic call control[16].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's cites work is recorded as ISDN user-network interface - Data link layer specification — cites work (P2860): Recommendation X.1 (11/1988): International user classes of service in public data networks and integrated services digital networks (ISDNs)[17].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's cites work is recorded as ISDN user-network interface - Data link layer specification — cites work (P2860): Recommendation X.2 (11/1988): International data transmission services and optional user facilities in public data networks and ISDNs[18].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's cites work is recorded as ISDN user-network interface - Data link layer specification — cites work (P2860): Recommendation X.25 (11/1988): Interface between data terminal equipment (DTE) and data circuit-terminating equipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit[19].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's cites work is recorded as ISDN user-network interface - Data link layer specification — cites work (P2860): Recommendation X.3 (11/1988): Packet assembly/disassembly facility (PAD) in a public data network[20].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's cites work is recorded as ISDN user-network interface - Data link layer specification — cites work (P2860): Recommendation X.4 (11/1988): General structure of signals of International Alphabet No. 5 code for character oriented data transmission over public data networks[21].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's cites work is recorded as ISDN user-network interface - Data link layer specification — cites work (P2860): Recommendation X.5 (02/1992): Facsimile Packet Assembly/Disassembly facility (FPAD) in a public data network[22].
  • Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's ITU-T Recommendation is recorded as ISDN user-network interface - Data link layer specification — ITU-T Recommendation (P5688): Q.921 (11/1988)[23].

Body

Authorship and Creation

Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's publisher is recorded as ISDN user-network interface - Data link layer specification — publisher (P123): ITU Telecommunication Standardization Sector[3].

Publication

Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification's publication date is recorded as +1988-11-25T00:00:00Z[6]. Its language of work or name is recorded as ISDN user-network interface - Data link layer specification — language of work or name (P407): English[5].

References

Programmatic citations — every numbered marker resolves to a verifiable graph row below.

Direct Wikidata claims

  1. [2] ↑ . wikidata.org.
  2. [3] ↑ . wikidata.org.
  3. [4] ↑ . wikidata.org.
  4. [5] ↑ . wikidata.org.
  5. [6] ↑ . wikidata.org.
  6. [7] ↑ . wikidata.org.
  7. [8] ↑ . wikidata.org.
  8. [9] ↑ . wikidata.org.
  9. [10] ↑ . wikidata.org.
  10. [11] ↑ . wikidata.org.
  11. [12] ↑ . wikidata.org.
  12. [13] ↑ . wikidata.org.
  13. [14] ↑ . wikidata.org.
  14. [15] ↑ . wikidata.org.
  15. [16] ↑ . wikidata.org.
  16. [17] ↑ . wikidata.org.
  17. [18] ↑ . wikidata.org.
  18. [19] ↑ . wikidata.org.
  19. [20] ↑ . wikidata.org.
  20. [21] ↑ . wikidata.org.
  21. [22] ↑ . wikidata.org.
  22. [23] ↑ . wikidata.org.

Class ancestry

  1. [1] ↑ . Wikidata. wikidata.org.

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APA 4ort.xyz Knowledge Graph. (2026). Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification. Retrieved May 3, 2026, from https://4ort.xyz/entity/recommendation-q-921-11-1988-isdn-user-network-interface-data-link-layer-specification
MLA “Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification.” 4ort.xyz Knowledge Graph, 4ort.xyz, 3 May. 2026, https://4ort.xyz/entity/recommendation-q-921-11-1988-isdn-user-network-interface-data-link-layer-specification.
BibTeX @misc{4ortxyz_recommendation-q-921-11-1988-isdn-user-network-interface-data-link-layer-specification_2026, author = {{4ort.xyz Knowledge Graph}}, title = {{Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification}}, year = {2026}, url = {https://4ort.xyz/entity/recommendation-q-921-11-1988-isdn-user-network-interface-data-link-layer-specification}, note = {Accessed: 2026-05-03}}
LLM prompt According to 4ort.xyz Knowledge Graph (aggregator of Wikidata, Wikipedia, and authoritative open-data sources): Recommendation Q.921 (11/1988): ISDN user-network interface - Data link layer specification — https://4ort.xyz/entity/recommendation-q-921-11-1988-isdn-user-network-interface-data-link-layer-specification (retrieved 2026-05-03)

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