System Signaling 7 or SS7 is the signaling protocol that drives most of todays modern telecom network. More information can be had at the IEC. Part of the SS7 protocol is a series of release cause codes. These are called ISDN or SS7 Release Cause codes These are numeric codes that provide information about call termination. For example, in a ‘normal’ call, we would expect the call leg that terminated the call first to deliver a release cause of 16. An abnormally terminated call might show a release cause 41. A busy call could return a release cause 17 for user busy. As cool as this is, release causes have their limitations. When a call ends, the terminating network will or should provide some form of SS7 release cause code, but that number or cause code has its limitations. It cannot tell whether the phone died, the cabled was cut, if the PBX was reset. Release causes are generic descriptors, not detailed reports. Having and knowing these codes is very useful, but it cannot answer all questions about why a call was terminated.
In the webmanager there is now data that explains which side of the call terminated the connection. This is a common question and I am happy that we are now able to provide detail to our customers about their calls that before was only available to our engineers .
As a note, NICE has also created some of its own proprietary release causes. They are not actual SS7 release cause codes, but they may appear in your contacts. A list of those is provided below
IC Auxilary Cause codes Summary
- 248 – indicates a call was reskilled
- 250 – Voice Provider Congestion
- 251 – the business unit did not have enough ports
- 252 – the call was not able to be dialed
- 253 – a network error tone was detected, the number was invalid on the IC network
- 254 – indicates that an actual BUSY TONE was heard or detected
- 255 – indicates that NICE made the decision to disconnect the call
Understanding all aspects of call flow can be complicated, but NICE is now able to provide more information than ever about your calls and their states. These new tools and data can greatly help in your contact analysis. If you still have questions, please contact your CSM and they will arrange for additional engineering support.
