sip media · stub
ITU-T Q.850 call clearing cause values
Verified 2026-09-15 · 19 claims · sources tier 1–2
Also known as Q.850, Q.850 cause codes, call clearing cause, cause value, interworking unspecified, normal call clearing.
Stub. This topic has 19 verified claims and no published article. The claims below are exactly what the corpus holds today.
So far, no summary has been generated for this topic. The claims below are what the corpus currently holds.
See also
Related to
- CUCM CDR and CMR field referencestub — CUCM call detail record cause values are Q.850 values plus Cisco-specific additions
- SIP response codes — Cause 13 is defined as SIP behaviour and CUCM SIP cause codes carry a Q.850 value in their low word
Referenced by
- CUCM CDR and CMR field referencestub — The specification the cause column of a call detail record is defined by
- SIP response codes — The cause vocabulary a SIP status code is mapped onto in a gateway or a call detail record
Claims
| # | Claim | Status | Confidence | Verified |
|---|---|---|---|---|
| 1 | Unified CM publishes call termination cause codes beyond the Q.850 set, marked Cisco specific in the table, including 125 out of bandwidth, 126 call split, 131 Call Control Discovery PSTN failover and a run of IME failure codes through 148. Call Detail Records Administration Guide for Cisco Unified Communications Manager Release 12.5(1), complete book, Internet Archive capture of 2025-03-23 · Call Detail Records chapter, Call Termination Cause Codes, Table 12 | fact | 0.90 | 2026-09-15 |
| 2 | For on-net call legs Unified CM determines the cause code value and for off-net legs the far-end switch determines it, so a cause on an off-net leg is a foreign network's statement carried through rather than Unified CM's own diagnosis. Call Detail Records Administration Guide for Cisco Unified Communications Manager Release 12.5(1), complete book, Internet Archive capture of 2025-03-23 · Call Detail Records chapter, Call Clearing Causes | fact | 0.90 | 2026-09-15 |
| 3 | Every one of the 42 SIP rows of the Cisco-specific cause code table has a Q.850 cause value in the low 16 bits of its code, and the guide states the construction for one row by writing the loop-detected code as 0x42000000 plus EXCHANGE_ROUTING_ERROR. Call Detail Records Administration Guide for Cisco Unified Communications Manager Release 12.5(1), complete book, Internet Archive capture of 2025-03-23 · Call Detail Records chapter, Table 13 Cisco-Specific Call Termination Cause Codes | field-pattern | 0.90 | 2026-09-15 |
| 4 | Cause 127 interworking unspecified indicates interworking with a network that does not provide causes for its actions, so the precise cause cannot be ascertained. | fact | 0.90 | 2026-09-15 |
| 5 | Cause 13 call completed elsewhere is the one Q.850 cause whose application column reads SIP rather than DSS 1 or ISUP, and its definition is a rule about what an S-CSCF puts in the Reason header field of a CANCEL after a forked INVITE receives a 2xx. 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 · Table 1 row for cause 13 and clause 6.2.7.1.10 Cause No. 13 | fact | 0.90 | 2026-09-15 |
| 6 | Cause 16 normal call clearing indicates that one of the users involved requested that the call be cleared, and Q.850 states that under normal situations the source of this cause is not the network. | fact | 0.90 | 2026-09-15 |
| 7 | Cause 18 no user responding is used when the called party does not respond to call establishment within the allotted time, while cause 19 no answer from user is used when the called party was alerted and did not answer, so the pair separates a device that never signalled from a device that rang. | fact | 0.90 | 2026-09-15 |
| 8 | Cause 41 temporary failure and cause 38 network out of order both indicate that the network is not functioning correctly and are separated only by expected duration: a 41 invites an immediate retry and a 38 says an immediate retry is not likely to succeed. | fact | 0.90 | 2026-09-15 |
| 9 | A Q.850 cause value is a class in bits 5 to 7 and a value within the class in bits 1 to 4, so the cause number is the class times 16 plus the value, and that arithmetic holds for all 70 cause values in Table 1. | field-pattern | 0.90 | 2026-09-15 |
| 10 | Two bits of the cause element select the coding standard as ITU-T standardized, ISO/IEC, national, or specific to the identified location, and Q.850 states the other standards should be used only when the desired cause value cannot be represented with ITU-T coding. | fact | 0.90 | 2026-09-15 |
| 11 | The diagnostics that may accompany a cause are given per cause value in Table 1 and Q.850 states that diagnostic information is not available for every cause. | fact | 0.90 | 2026-09-15 |
| 12 | Each Q.850 class carries an unspecified cause used only when no other cause in that class applies, and the definitions say so in the same words for each: 31 normal, 47 resource unavailable, 63 service or option not available, 79 service or option not implemented, 95 invalid message, 111 protocol error and 127 interworking. 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 · clauses 6.2.7.1.25, 6.2.7.2.10, 6.2.7.3.8, 6.2.7.4.5, 6.2.7.6.10 and 6.2.7.7.1 | field-pattern | 0.90 | 2026-09-15 |
| 13 | The in-force components of Q.850 are the edition of 10/2018 and Amendment 1 of 04/2019, and the 1993 and 1998 editions are listed as superseded. 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 · ITU-T recommendation landing page, In force components table | fact | 0.60 | 2026-09-15 |
| 14 | Causes carried in the ISDN user part and not marked for national use are the minimum set of cause values that shall be supported over the international interface. | fact | 0.90 | 2026-09-15 |
| 15 | Location is a separate four-bit field of the same cause element with 8 defined values from user through international network and network beyond interworking point, so a cause value quoted without its location does not say who cleared the call. | fact | 0.90 | 2026-09-15 |
| 16 | The normal class holds 25 of the 70 Q.850 causes, more than any other class, and the interworking class holds exactly one. | field-pattern | 0.90 | 2026-09-15 |
| 17 | ITU-T Q.850 defines 70 cause values and every one of them is both a row of Table 1 and a numbered definition subclause under clause 6.2.7; the two lists are identical. 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 · Table 1 Cause information element/parameter and clause 6.2.7 Cause definitions | fact | 0.90 | 2026-09-15 |
| 18 | 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. 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 · Figure 1 Format of Cause, notes 1 and 2, and clause 6.2.4 | fact | 0.90 | 2026-09-15 |
| 19 | Clause 6.2.5 names class 000 and class 001 both as normal event, and clause 6.2.7 groups both under a single heading called the Normal class, so the eight class codes carry seven names. 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 · clause 6.2.5 Cause value, class list, and clause 6.2.7.1 Normal class | fact | 0.90 | 2026-09-15 |
Sources
Cite this page
APA
WarmTransfer. (2026, September 15). ITU-T Q.850 call clearing cause values. WarmTransfer. https://warmtransfer.net/knowledge/q850-cause-codes
BibTeX
@misc{warmtransfer-q850-cause-codes,
title = {ITU-T Q.850 call clearing cause values},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/q850-cause-codes},
note = {Verified 2026-09-15}
}