# Create a SIP Extension

A SIP (Session Initiation Protocol) extension is the account a desk phone or softphone registers against so a user can place and receive calls. This page walks through adding one and setting the user details, language preferences, and registration credentials that go with it.

## Add the extension

1. Sign in to the Cloud Voice management portal and go to **Extension and Trunk > Extension**. Click **Add**, then choose **Add**.

2. Fill in the **User Information** section.

   - (Optional) Add an avatar for the extension:

   1. Click the camera icon ![Camera icon for uploading an avatar](/images/pbx/camera.png).
   2. In the file picker, select an image from your computer and click **Open**.

        :::note
        The image must be a `.jpg` or `.png` file no larger than 1 MB.
        :::
   3. Position the image as you want it to appear, then click **Upload**.

     :::tip
     Users can also set their own avatar from the Cloud Voice App, so you can leave this blank and let them personalize it later.
     :::

   - Complete the basic user details:

     | Setting | Description |
     |---------|-------------|
     | First Name | The user's first name. |
     | Last Name | The user's last name. |
     | Email Address | The user's email address. It is used to sign in to the management portal and the Cloud Voice App, and to deliver voicemail messages and system notifications. Each email address can belong to only one user. |
     | Mobile Number | The user's mobile number. Calls and system notifications can be delivered to it. |
     | User Password | The password the user enters to sign in to the Cloud Voice App. |
     | User Role | The role that determines which phone system features the user is allowed to manage. It defaults to **None**, meaning the user manages no administrative features. The system ships with [predefined roles](/pbx/administrator-guide/user-roles-and-permissions/#user-roles-and-permissions__section_pph_jft_llb), or you can [create your own](/pbx/administrator-guide/create-a-user-role/). |
     | Organization | One or more organizations the extension belongs to. This field appears only when Organization Management is enabled. |
     | Job Title | A job title for the user. It is shown in the Cloud Voice App. |

3. In the **Language** section, choose the language preferences for the extension.

   | Setting | Description |
   |---------|-------------|
   | Notification Email Language | The language used in system-generated email notifications sent to this extension. Choosing **Follow System** applies the language set under **System > Email > Email Templates > Notification Email Language**. This applies to default system emails only; it has no effect on customized email templates. |
   | System Prompt Language | The language of the system prompts the user hears during a call. The available choices come from the installed system prompts under **PBX Settings > Voice Prompt > System Prompt**. |
   | Voicemail Language | The language of the voicemail prompts a caller hears when reaching this extension's voicemail. The available choices come from the same system prompts under **PBX Settings > Voice Prompt > System Prompt**. If the extension has a [custom voicemail greeting](/pbx/administrator-guide/change-voicemail-greetings/#upload-voicemail-greetings__section_zpq_5cz_klb), that greeting plays instead and this language setting is ignored. |

4. In the **Extension Information** section, set the extension number and registration credentials.

   | Setting | Description |
   |---------|-------------|
   | Extension Number | The number assigned to the extension. It can be up to 11 characters long. |
   | Caller ID | The caller ID number shown on the called party's device. |
   | Registration Name | The name a SIP device uses to register the extension. A random value is generated by default. |
   | Registration Password | The password a SIP device uses to register the extension. A random value is generated by default. For security, set a strong password. |
   | IP Phone Concurrent Registrations | How many SIP phones can register with the extension at the same time. The maximum is 5. |
   | Cloud Voice App Web Client Concurrent Registrations | How many Cloud Voice App web sessions can be signed in to the extension at once. The maximum is 3. |
   | Cloud Voice App Desktop Client Concurrent Registrations | How many Cloud Voice App desktop sessions can be signed in to the extension at once. The maximum is 3. |
   | Cloud Voice App Mobile Client Concurrent Registrations | How many Cloud Voice App mobile sessions can be signed in to the extension at once. The maximum is 3. |

   :::caution
   The Registration Name and Registration Password are the credentials a device sends to log in to the phone system, and they are separate from the User Password set in step 2. A weak or shared registration password is a common route for toll fraud, where an attacker registers to the extension and places expensive calls at your expense. Keep the randomly generated values or set a strong, unique password, and do not reuse the User Password here.
   :::

5. (Optional) In the **Outbound Caller ID (DOD)** section, define the outbound caller IDs this extension may use. DOD stands for Direct Outward Dialing: the number that the called party sees when the user makes an external call. See [Allow Users to Select Outbound Caller ID (DOD) to Call](/pbx/administrator-guide/allow-users-to-select-outbound-caller-id-dod-to-call/) for details.

6. (Optional) In the **Permission Configuration** section, add the extension to extension groups or remove it from ones it belongs to, and [manage the user types and permissions](/pbx/administrator-guide/view-or-change-a-member-user-type-in-multiple-groups/#assign-user-types-to-multiple-memebers__section_mlg_rjf_wnb) it has within those groups.

7. (Optional) Use the remaining tabs to adjust any other settings the extension needs.

8. Click **Save**, then **Apply**.

   :::note
   Save stores the extension, but the configuration does not go live until you click Apply. If a newly created extension will not register on a device, first confirm that Apply was clicked.
   :::

## Result

The SIP extension is created and ready for a device to register against it.

## What to do next

Register the extension on a phone. See [Set Up a SIP Phone](/pbx/administrator-guide/set-up-a-sip-phone/).