VOS3000 Call Termination Reasons Dictionary: Important Full Reference Guide – Call End Reason
When troubleshooting call failures in VOS3000, the termination reason shown in CDRs is your most valuable diagnostic tool. However, many of these reasons are cryptic or misunderstood. This comprehensive VOS3000 termination reasons dictionary explains every possible call end code – both server‑generated and those received from connected devices.
Bookmark this page for quick reference whenever you encounter unexpected call failures.
Table of Contents
How VOS3000 Call Termination Reasons Records
Every CDR in VOS3000 includes a termination reason field. This value tells you exactly why the call ended – whether it was rejected, timed out, hung up normally, or failed due to an error. Reasons come from three sources:
- Server‑side – generated by the VOS3000 softswitch itself
- H.323 device – received from the far‑end H.323 gateway or terminal
- SIP device – received from the far‑end SIP equipment (as response codes)
Understanding these codes helps you pinpoint whether the problem is with your configuration, your carrier, or the destination network.
Server‑Side VOS3000 Call Termination Reasons (VOS3000 Generated)
These reasons are created by the VOS3000 softswitch when it decides to terminate a call. They often indicate configuration issues, resource limitations, or policy enforcement.
| Termination Reason | Description | Typical Cause |
|---|---|---|
| Response timeout | The called party did not answer within the configured timeout period. | Phone offline, network congestion, or wrong routing gateway. |
| Protocol limit | The server cannot process this protocol type. | Mixing SIP and H.323 incorrectly; incompatible protocol settings. |
| Connection timeout | No response to SIP messages after multiple retries. | Far end down, firewall blocking, or network issues. |
| Busy | The called number is busy. | Destination line engaged; call forwarded to busy tone. |
| Account locked | The billing account is disabled. | Account manually locked, expired, or parent agent locked. |
| Session timeout | SIP session timer expired (no re‑INVITE received). | Far end stopped responding; network failure. |
| Caller’s number restricted | Caller number length exceeds allowed limit. | Wrong rewrite rule; caller ID too long for carrier. |
| Called number restricted | Callee number length exceeds allowed limit. | Incorrect dialing; number too long/short. |
| Proceeding timeout | No response after initial SETUP/INVITE. | Routing gateway not responding; carrier down. |
| Caller’s number prefix restricted | Mapping gateway rejects caller prefix. | Caller ID blocked by gateway settings. |
| Unregistered | Terminal not registered and not allowed to call. | Dynamic gateway/phone not registered. |
| Called number locked | The destination number is locked in the system. | Phone locked via web interface. |
| Called number prefix restricted | Routing gateway rejects callee prefix. | Carrier does not terminate that prefix. |
| Caller locked | The calling device is locked. | Gateway/phone locked in configuration. |
| Connection establishment timeout | Call not established within mapping gateway timeout. | Media path failure; far end not responding. |
| Account expired | The billing account has passed its expiry date. | Customer did not recharge on time. |
| Connection limit exceeded | Maximum concurrent calls reached for this gateway/account. | Too many simultaneous calls; need more capacity. |
| Forcible hang‑up | Server disconnected the call (admin action). | Admin clicked “disconnect” in client. |
| Account disabled | The account is disabled (not just locked). | Account marked as disabled by admin. |
| The called not online | No suitable device to receive the call. | No matching routing gateway; phone offline with no forwarding. |
| No‑answer forwarding by the caller | Caller‑side forwarding on no‑answer activated. | Caller set CFNR; call redirected. |
| Timed forwarding | Call matched time‑based forwarding rule. | Forwarding based on time of day. |
| On‑busy forwarding | Call matched busy forwarding rule. | Destination busy; forwarded. |
| No‑answer forwarding by the called | Callee‑side CFNR activated. | Phone not answered; forwarded. |
| Forwarding loop | Forwarding rules created an infinite loop. | Misconfigured call forwarding. |
| Call forwarding by the called | Unconditional call forwarding on callee side. | Phone set to forward all calls. |
| Do‑not‑disturb from the called | Callee has DND enabled. | Phone in DND mode. |
| Session closed by the called | Called party closed TCP connection without BYE. | Device crash; network disconnect. |
| Session closed by the caller | Caller closed TCP connection without BYE. | Device crash; network disconnect. |
| Illegal call | Call from unauthorized IP and unregistered number. | Hacker attempt; misconfigured gateway. |
| No matching rate | No rate found for the dialed number. | Missing rate prefix; incomplete rate card. |
| No matching account | No billing account linked to the caller. | Mapping gateway not linked to account. |
| Insufficient balance | Account balance below zero (including overdraft). | Customer ran out of credit. |
| Call restriction | Call prevented by phone/gateway restrictions. | International blocking; blacklist. |
| Hang‑up by the called | Called party sent normal BYE. | Normal call end. |
| Hang‑up by the caller | Caller sent normal BYE. | Normal call end. |
SIP Device Termination Reasons (Response Codes) – VOS3000 Call Termination
When a call fails because of the remote SIP device, VOS3000 records the SIP response code received. Here are the most common ones:
| SIP Code | Reason Phrase | Meaning |
|---|---|---|
| 401 | Unauthorized | Authentication failed – wrong password or missing credentials. |
| 403 | Forbidden | Call rejected by remote side (blacklist, policy). |
| 404 | Not Found | Number does not exist on remote network. |
| 486 | Busy Here | Destination line busy. |
| 487 | Request Terminated | Call cancelled (e.g., caller hung up before answer). |
| 488 | Not Acceptable Here | Codec mismatch – no common codec. |
| 503 | Service Unavailable | Remote server overloaded or down. |
| 504 | Server Time‑out | Gateway did not respond in time. |
| 603 | Decline | Call rejected by user (DND, reject). |
H.323 Device Termination Reasons – VOS3000 Call Termination
H.323 devices return Q.931 cause codes. Common ones include:
| Q.931 Cause | Description | Typical Cause |
|---|---|---|
| 1 | Unallocated number | Number not in service. |
| 3 | No route to destination | Network unreachable. |
| 16 | Normal call clearing | Normal hang‑up. |
| 17 | User busy | Destination busy. |
| 18 | No user responding | No answer (ring timeout). |
| 21 | Call rejected | Rejected by remote side. |
| 22 | Number changed | Number ported; redirect. |
| 27 | Destination out of order | Far end equipment failure. |
| 28 | Invalid number format | Wrong dialed digits. |
| 34 | No circuit/channel available | All trunks busy. |
| 38 | Network out of order | Carrier network failure. |
| 41 | Temporary failure | Transient network error – retry. |
| 42 | Switching equipment congestion | Overload at exchange. |
| 47 | Resource unavailable | Codec or channel resource issue. |
How to Use This Information for Troubleshooting – VOS3000 Call Termination
When you see a call failure, follow this process:
- Check the termination reason in the CDR.
- Identify the source – server, SIP, or H.323.
- Look for patterns – does it happen to one prefix, one gateway, or all calls?
- Examine logs – use “Call Analysis” in the VOS3000 client to see the full signaling exchange.
- Check configurations – rates, blacklists, number lengths, account balances.
- Test with routing analysis – simulate the call to see which gateway would be chosen.
Frequently Asked Questions (VOS3000 Call Termination)
What does “No matching rate” mean?
This means the dialed number’s prefix did not match any rate in the rate group assigned to the caller’s account. You need to add the missing rate prefix or adjust the caller’s rate group.
Why do I see “Illegal call” in CDRs?
“Illegal call” means the incoming IP address was not recognized as a valid mapping gateway, and the caller number did not match any registered phone. This is often a hacking attempt – block the IP immediately and review your firewall rules.
What causes “488 Not Acceptable Here”?
This SIP error means the remote gateway does not support any of the codecs offered by your system. Check codec settings on both sides and ensure at least one common codec (e.g., G.729, G.711) is enabled.
How do I distinguish between a local hang‑up and a remote hang‑up?
The CDR field “Hangup side” tells you: 0 = caller, 1 = callee, 2 = server. Combined with termination reason, you can see exactly who ended the call and why.
My CDR shows “Response timeout” – what should I check?
First, verify the routing gateway is online and reachable. Then check if the remote side is answering other calls. If only specific prefixes fail, the carrier may not be sending progress signals – increase the timeout settings in the routing gateway configuration.
Conclusion – VOS3000 Call Termination
Understanding VOS3000 termination reasons is the fastest path to resolving call failures. Bookmark this reference and refer to it whenever you encounter an unfamiliar code. With practice, you’ll be able to diagnose most issues in seconds.
Need help troubleshooting persistent call failures? Contact us on WhatsApp for expert assistance: +8801911119966
Further Resources
- VOS3000 Official Site
- VOS3000 Official Blog
- VOS3000 Downloads
- Multahost Blog
- NoAvailableRouter Error Explained
- Error Code Replacement Guide
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