# Configure SIP Cause Code and Q850 Mapping

Class 4 Fusion let you configure Q850 mapping with SIP Cause Code.  You can configure this mapping in this config file:

```
/opt/denovo/dnl_softswitch/conf/sip_response_to_q850.conf
```

Here is how it looks like:

```
sip_response,QSIG
200,16
400,41
401,21
402,21
403,21
404,1
405,63
406,79
407,21
408,102
410,22
413,127
414,127
415,79
416,127
420,127
421,127
423,127
480,18
481,41
482,25
483,25
484,28
485,1
486,17
487,487
488,65
500,41
501,79
502,38
503,34
504,102
505,127
513,127
600,17
603,21
604,1
606,65
```

{% hint style="info" %}
By default, this file does not exist, so you will need to create it under the /conf directory.
{% endhint %}

After you modify this sip\_response\_toq850.conf file, you will need to restart the swith using the following command:

```
systemctl restart dnl_softswitch
```


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