What are SIP Codes?
SIP (Session Initiation Protocol) codes are standardized numeric responses used in VoIP telephony to indicate the status of a call attempt.
SIP codes help communicate what happened at each stage of a call, from dialing to answering, to busy signals and failures.
Why SIP Codes Matter
SIP codes help to:
- Accurately track call outcomes.
- Automate call Disposition assignments.
- Troubleshoot call connection issues.
- Improve Campaign and dialing strategy decisions.
Understanding these codes helps in interpreting why calls succeed or fail and how to then optimize workflows.
Common SIP Codes
| SIP Code | Description | Call Outcome/Disposition |
|---|---|---|
| 200 | OK – Call answered successfully | Connected, Sale, or Call Completed |
| 180 | Ringing | Call is ringing on the recipient’s end |
| 486 | Busy Here | Busy Signal, Call Rejected |
| 480 | Temporarily Unavailable | No Answer, Call Not Picked Up |
| 408 | Request Timeout | Call Timeout, No Response |
| 603 | Decline | Call Declined by Recipient |
| 404 | Not Found | Invalid Number, Number Does Not Exist |
| 403 | Forbidden | Call Blocked, Authentication or Permission Error |
| 503 | Service Unavailable | Network or Server Busy, Temporary Failure |
| 487 | Request Terminated | Call Cancelled by Caller or System |
SIP Codes in Call Handling
- Call Retry Logic:
Some SIP codes (like 480 or 503) trigger automatic call retries later. - Disposition Assignment:
SIP codes map to call outcome statuses used in reporting and lead management. - Troubleshooting:
SIP codes help pinpoint whether failures are due to busy lines, invalid numbers, or network errors. - Compliance:
Codes like 403 help flag calls blocked due to regulatory or blacklist rules.
Dispositions & Associated SIP Codes
| Convoso Disposition | Associated SIP Code(s) | Description |
|---|---|---|
| Connected/Sale | 200 OK | Call was answered successfully. |
| Busy | 486 Busy Here | The called party was busy. |
| No Answer/No Pickup | 480 Temporarily Unavailable 408 Request Timeout | Call was not answered, or timed out. |
| Declined | 603 Decline | Call was actively rejected by the recipient. |
| Failed/Call Failed | 503 Service Unavailable 500 Server Internal Error | Network or server error prevented call completion. |
| Not Found/Invalid Number | 404 Not Found | Number dialed does not exist. |
| Forbidden/Blocked | 403 Forbidden | Call rejected due to permissions or blacklisting. |
| Cancelled | 487 Request Terminated | Call was canceled by the caller or system. |
| Congestion | 486 Busy Here 503 Service Unavailable | Network congestion or overloaded server. |
What to Do When You See SIP Errors
| Busy (486) | Wait and retry the Lead later. |
| Decline (603) | Usually no retry needed. Consider removing or reassigning the Lead. |
| Forbidden (403) | Check permissions, API keys, or carrier restrictions. |
| Service Unavailable (503) | Network or system issue. Monitor and retry later. |
| Not Found (404) | Confirm the phone number’s accuracy or remove the Lead. |