{"id":9013,"number":"26.541","type":"TS","title":"Ultra Low Bitrate Speech Codec (ULBC); C reference software and model formats","series":26,"status":"Draft","initial_release":"Rel-20","primary_group":"S4","secondary_groups":[],"portal_id":5540,"portal_url":"https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=5540","dynareport_url":"https://www.3gpp.org/dynareport/26541.htm","publication_scope":null,"radio_technologies":[],"first_seen_at":"2026-09-16T11:13:24.179994+00:00","updated_at":"2026-10-16T09:34:55.609033+00:00","raw_metadata":{"source_url":"https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=5540"},"detail_synced_at":"2026-10-08T00:25:28.280488+00:00","versions":[],"release_presence":[],"classifications":[],"work_items":[{"uid":1120096,"acronym":"ULBC-MED","effective_acronym":"ULBC-MED","title":"Ultra Low Bitrate Speech Codec for IMS Voice Call over NB-IoT NTN via GEO Satellite","responsible_groups":["S4"],"release":"Rel-20","status":"PCG approved","wi_level":"Building Block (2nd level)","type":"Work Item","first_release":null,"last_release":null,"provenance_type":"official","source_url":"https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=5540","association_sources":[],"association_status":"historical_unverified"}],"change_requests":[],"relationships":[],"relationship_release_evidence_summary":[],"relationship_release_evidence":[],"relationship_release_evidence_meta":{"total":0,"returned_count":0,"limit":100,"truncated":false,"href":"/api/specs/26.541/relationship-evidence"}}