Carrier Implementations
Unfortunately although the standards exist for how these codes should be implemented, the reality (globally) is that carriers all differ, and will return different codes for the same scenarios.
This is something we try to normalize but is not a simple task. The dialer and Click2Dial v2.3.0+ are much more advanced in this regards and does a lot more work to normalize the data then Click2Dial pre v2.3.0.
Prefer Dispositions to ISDN codes, they may not vary as much, but are more accurate because we handle the mapping and normalizing for you.
| Code | ISDN Cause codes (Q.850 & Q.931 unless specified) | SIP/PJSIP | Motif |
|---|---|---|---|
Cause not defined | |||
| 1 | Unallocated (unassigned) number | 404, 485, 604 | |
| 2 | No route to specified transmit network | 404 | |
| 3 | No route to destination | 404, 420 | |
| 5 | Misdialled trunk prefix (national use) | ||
| 6 | Channel unacceptable | ||
| 7 | Call awarded and being delivered in an established channel | ||
| 8 | ISUP - Preemption | ||
| 14 | QoR: ported number | ||
| 16 | Normal Clearing | 200, 202, 204 | gone, success |
| 17 | User busy | 486, 600 | busy |
| 18 | No user responding | 408 | expired |
| 19 | No answer from user (user alerted) | 480, 483 | |
| 20 | Subscriber absent | 480 | |
| 21 | Call Rejected | 401, 403, 407, 603 | cancel, decline |
| 22 | Number changed | 410 | |
| 23 | Redirected to new destination | 410 | |
| 26 | Non-selected user clearing (ASTERISK-15057) | 404 | |
| 27 | Destination out of order | 502 | |
| 28 | Invalid number format | 484 | |
| 29 | Facility rejected | 501 | |
| 30 | Response to STATUS ENQUIRY | ||
| 31 | Normal, unspecified | 480 | Temporarily unavailable |
| 34 | No circuit/channel available (Note that we've called this "Circuit/channel congestion" for a while which can cause confusion with code 42) | 503 | general-error |
| 38 | Network out of order | 500, 503 | |
| 41 | Temporary failure | 409, 503 | |
| 42 | Switching equipment congestion | 503 | failed-application |
| 43 | Access information discarded | ||
| 44 | Requested circuit/channel not available | ||
| 50 | Requested facility not subscribed | ||
| 52 | Outgoing call barred | ||
| 54 | Incoming call barred | ||
| 57 | Bearer capability not authorized | ||
| 58 | Bearer capability not presently available | 488, 606 | incompatible-parameters, media-error, unsupported-applications |
| 65 | Bearer capability not implemented | ||
| 66 | Channel type not implemented | ||
| 69 | Requested facility not implemented | unsupported-transports | |
| 81 | Invalid call reference value | ||
| 88 | Incompatible destination | ||
| 95 | Invalid message unspecified | ||
| 96 | Mandatory information element is missing | ||
| 97 | Message type non-existent or not implemented | ||
| 98 | Message not compatible with call state or message type non-existent or not implemented | ||
| 99 | Information element nonexistent or not implemented | ||
| 100 | Invalid information element contents | ||
| 101 | Message not compatible with call state | ||
| 102 | Recover on timer expiry | 504 | timeout |
| ? | Mandatory IE length error | ||
| 111 | Protocol error, unspecified | failed-transport, security-error | |
| 127 | Interworking, unspecified | 4xx, 505, 6xx | connectivity-error |