# How do I set my own sender number in a 3CX phone system?

As a 3CX user in conjunction with sipgate trunking, you have the option of setting a **freely selectable caller ID** for each extension.

The caller ID for the individual extensions can be set in a 3CX phone system as follows:

{% stepper %}
{% step %}
**Select extension**

First, select the extension to be configured in the 3CX system menu.
{% endstep %}

{% step %}
**Enter phone number**

Then go in the menu to **General ➔** **Outgoing caller ID**. Enter the desired number here in **E164 format** (49xxxxx / without plus sign or leading zeros).
{% endstep %}
{% endstepper %}

{% hint style="info" %}
If the caller ID is not set here, the called party will see the **Fallback sender number** that you can find in the logged-in area of your sipgate account under **Trunking** .
{% endhint %}


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