# Control a Fanvil IP Phone from the Cloud Voice App

CTI (Computer Telephony Integration) mode links a Fanvil desk phone to your Cloud Voice App (web) session. Once connected, the web client becomes an on-screen control panel for the phone: you click to answer, hold, transfer, and manage calls, while the audio and the actual call legs stay on the Fanvil handset.

## Where this applies

This method works with Fanvil desk phones that support Cloud Voice App CTI. To confirm your model is on the list, see the [CTI overview](/pbx/web-client-user-guide/cloud-voice-app-web-client-cti-overview/#linkus-web-client-cti__compatible-fanvil).

:::tip
Using a phone that isn't on the compatible list? Follow [Control an Incompatible IP Phone from the Cloud Voice App](/pbx/web-client-user-guide/remotely-control-an-incompatible-ip-phone-by-cloud-voice-app-web-client/) instead.
:::

## Before you start

Make sure the following are in place:

- **On the phone system**: uaCSTA must be turned on under **PBX Settings > SIP Settings > Advanced > Other Options > Enable uaCSTA Connection**. uaCSTA (user agent Computer Supported Telecommunications Applications) is the channel that lets the app send control commands to the phone. SIP (Session Initiation Protocol) is the standard the phone uses to register with the phone system.
- **On the desk phone**: the extension registered on the Fanvil phone must match the extension you sign in with on the Cloud Voice App.

:::caution
Register only one account on the Fanvil phone. Additional accounts can stop CTI from working.
:::

## Step 1. Make the phone controllable

:::note
If your administrator pushed your extension to the phone through Auto Provisioning, the phone is already set up for CTI. Skip ahead to [Step 2](#step-2-turn-on-cti-mode-in-the-cloud-voice-app).
:::

If your extension was registered on the phone by hand, enable uaCSTA and set a uaCSTA number on the phone itself. The steps below use a Fanvil X5S as the example.

1. Sign in to the phone's web interface and open **Line > SIP**.
2. From the **Line** drop-down, choose your extension.
3. Open the **Advanced Settings** section and type your extension number into the **uaCSTA Number** field.
4. Open the **SIP Global Settings** section and select **Enable uaCSTA**.
5. Click **Apply**.

## Step 2. Turn on CTI mode in the Cloud Voice App

Switching the web client to CTI mode is what lets you run the phone's calls from your browser.

1. Sign in to the Cloud Voice App (web).
2. In the top-right corner, click the CTI icon ![CTI mode toggle](/images/pbx/cti.png), then pick your connected Fanvil phone from the drop-down.

![Selecting a connected Fanvil phone to activate CTI mode](/images/pbx/fanvil-cti-mode.png)

## What you can do next

With the Fanvil phone connected, you can run these actions from the Cloud Voice App:

- Place and end calls
- Start a second call
- Answer or reject an incoming call
- Record a call
- Transfer a call, either attended or blind
- Hold and resume a call
- Swap between held calls
- Flip a call