|
ISUP (ISDN) Cause Value | Meaning |
SIP Status Code | Meaning |
| 1 | Unallocated number | 404 | Not Found |
| 2 | No route to specified transit network | 404 | Not Found |
| 3 | No route to destination | 404 | Not Found |
| 26 | Non-selected user clearing | 404 | Not Found |
| 16 | Normal call clearing (timeout waiting for the called party to answer) | 603 | Discard |
| 16 | Normal call clearing | 500 | Discard |
| 17 | User busy | 486 | Busy Here |
| 132 | Network busy (internal definition, ISDN only) | 486 | Busy Here |
| 21 | Call rejected | 486 | Busy Here |
| 18 | No user responding | 408 | Request Timeout |
| 19 | No answer from user (user has been alerted) | 480 | Temporarily Unavailable |
| 20 | Subscriber absent | 480 | Temporarily Unavailable |
| 31 | Normal, unspecified | 480 | Temporarily Unavailable |
| 136 | Connection failure after off-hook (internal definition, ISDN only) | 480 | Temporarily Unavailable |
| 137 | Off-hook timeout (internal definition, ISDN only) | 480 | Temporarily Unavailable |
| 55 | Incoming calls barred within CUG | 403 | Forbidden |
| 57 | Bearer capability not authorized | 403 | Forbidden |
| 87 | User is not a CUG member | 403 | Forbidden |
| 22 | Number changed | 410 | Gone |
| 27 | Destination out of order | 502 | Bad Gateway |
| 28 | Invalid number format | 484 | Address Incomplete |
| 29 | Facility rejected | 501 | Not Implemented |
| 79 | Service or option not implemented, unspecified | 501 | Not Implemented |
| 34 | No circuit / channel available | 503 | Service Unavailable |
| 38 | Network out of order | 503 | Service Unavailable |
| 41 | Temporary failure | 503 | Service Unavailable |
| 42 | Switching equipment congestion | 503 | Service Unavailable |
| 47 | Resource unavailable, unspecified | 503 | Service Unavailable |
| 58 | Bearer capability not presently available | 503 | Service Unavailable |
| 88 | Incompatible destination | 503 | Service Unavailable |
| 133 | Circuit reset (internal definition, ISDN only) | 503 | Service Unavailable |
| 134 | Temporary failure (internal definition, ISDN only) | 503 | Service Unavailable |
| 135 | Data link failure (internal definition, ISDN only) | 503 | Service Unavailable |
| 65 | Bearer capability not implemented | 488 | Not Acceptable Here |
| 70 | Only restricted digital information bearer capability is available | 488 | Not Acceptable Here |
| 102 | Recovery on timer expiry | 504 | Server Time-out |
| 128 | T303 timeout (internal definition, ISDN only) | 504 | Server Time-out |
| 129 | T304 timeout (internal definition, ISDN only) | 504 | Server Time-out |
| 130 | T310 timeout (internal definition, ISDN only) | 504 | Server Time-out |
| 111 | Protocol error, unspecified | 500 | Internal Server Error |
| 127 | Interworking, unspecified | 500 | Internal Server Error |
| Other | Other | 408 | Request Timeout |