# How to prohibit the replacement of "+" with 00

1. Go to the “**System**” section -> “**System file customization**”

<figure><img src="https://835495363-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FsZ8acWnNlSalIHQjMFu1%2Fuploads%2Fn06cIfMIqk6wJhcxD3gW%2FSystemFileCustomization.png?alt=media&#x26;token=4edfbfbf-6903-46c5-b1b5-d2a62131f59e" alt=""><figcaption><p>"System file customization" section</p></figcaption></figure>

2. Select the file “**/etc/asterisk/extensions.conf**” to edit.

<figure><img src="https://835495363-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FsZ8acWnNlSalIHQjMFu1%2Fuploads%2FNuELWVzuFh5rThr08jvu%2FEditExtensions.conf.png?alt=media&#x26;token=567dc075-00ed-45a7-bc10-915ccc1dc97f" alt=""><figcaption><p>"Extensions.conf" file</p></figcaption></figure>

3. Select the “**Add to end of file**” mode.

<figure><img src="https://835495363-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FsZ8acWnNlSalIHQjMFu1%2Fuploads%2Fz0OsKi2vZCi64tj7kfDT%2FAddToTheEndOfFileMode.png?alt=media&#x26;token=984f3c56-8c70-4520-acb8-ea8a553d07cb" alt=""><figcaption><p>“Add to end of file” mode</p></figcaption></figure>

4. Add the code to the second field:

{% code fullWidth="true" %}

```php
[outgoing](+)
exten => _+X!,1,Set(ADDPLUS=+);
    same => n,Goto(${CONTEXT},${EXTEN:1},1);
```

{% endcode %}

Save settings.

<figure><img src="https://835495363-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FsZ8acWnNlSalIHQjMFu1%2Fuploads%2FiWcMoYIuea8oK2qrsxS9%2FcodeFoExtensions.png?alt=media&#x26;token=9d7ec3c0-8ef3-46e1-a94c-a41a71408d39" alt=""><figcaption><p>Code for "extensions.conf"</p></figcaption></figure>

Now it's done :tada: