Source note · ITU-T Q.850 call clearing cause values
The Recommendation subfield of the cause element is not supported by the ISDN user part and its default interpretation there is Q.763, and when the field defaults the octets carrying it are omitted entirely rather than sent as zero.
Checked 2026-09-15
The Recommendation field is not supported by the ISUP. The default interpretation for ISUP is [ITU-T Q.763].
- Vendor
- ITU-T
- Product
- ITU-T Recommendation Q.850
- Subsystem
- Cause and location
- Deployment
- not restricted
- Region
- not restricted
- Release range
- edition 10/2018
- Checked
- 2026-09-15
Sources
- ITU-T Recommendation Q.850 (10/2018), Usage of cause and location in the Digital Subscriber Signalling System No. 1 and the Signalling System No. 7 ISDN user part — International Telecommunication Union (ITU-T) · tier 1 standards and regulators · Figure 1 Format of Cause, notes 1 and 2, and clause 6.2.4
Cite this note
APA
WarmTransfer. (2026, September 15). ITU-T Q.850 call clearing cause values: source note q850-the-recommendation-field-is-absent-in-isup. WarmTransfer. https://warmtransfer.net/knowledge/claims/q850-the-recommendation-field-is-absent-in-isup
BibTeX
@misc{warmtransfer-claim-q850-the-recommendation-field-is-absent-in-isup,
title = {ITU-T Q.850 call clearing cause values: source note q850-the-recommendation-field-is-absent-in-isup},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/q850-the-recommendation-field-is-absent-in-isup},
note = {Source note q850-the-recommendation-field-is-absent-in-isup, checked 2026-09-15}
}