# Control a Snom IP Phone from the Cloud Voice App Web Client

CTI (Computer Telephony Integration) mode links a Snom IP (Internet Protocol) phone that is registered with your extension to the Cloud Voice App Web Client. Once linked, calls are still placed and answered on the physical Snom phone, but you drive them from the web client, which acts as an on-screen control panel for the handset.

## Where this applies

These steps cover the [Snom IP phones that support Cloud Voice App Web Client CTI](/pbx/web-client-user-guide/cloud-voice-app-web-client-cti-overview/#linkus-web-client-cti__compatible-snom).

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

## Before you begin

Check the following with your system administrator, since these settings are managed on the phone system:

- The PBX (Private Branch Exchange, your phone system) server is running version **84.13.0.25** or later.
- The **uaCSTA** feature (the connection that carries control commands between the phone system and the handset) is turned on, under **PBX Settings > SIP Settings > Advanced > Other Options > Enable uaCSTA Connection**.

On the phone side, the Snom handset must be registered with the same extension you use in the Cloud Voice App Web Client.

:::caution
Register a single account on the Snom phone only. Adding more than one account can stop CTI from working.
:::

## Step 1: Make the Snom phone controllable

:::note
If your administrator provisioned your extension to the phone through Auto Provisioning, the handset is already set up for control. Skip ahead to [Step 2](#step-2-turn-on-cti-mode-in-the-web-client).
:::

When your extension was registered on the phone by hand, enable the CSTA (Computer-Supported Telecommunications Applications) control feature first. CSTA is the standard that lets the web client send call commands to the handset. The steps below use a Snom D735 as the example.

1. Sign in to the phone's web interface and open **Setup > Advanced > QoS/Security**.
2. Under the **Security** section, switch on **Allow CSTA Control**.

   ![Snom web interface with the Allow CSTA Control option enabled in the Security settings](/images/pbx/snom-advanced-setting.png)
3. Scroll to the bottom of the page and click **Apply**.

## Step 2: Turn on CTI mode in the web client

Switching the web client into CTI mode is what lets you manage the calls happening on your Snom phone.

1. Sign in to the Cloud Voice App Web Client.
2. In the top-right corner, click the CTI icon ![CTI mode icon](/images/pbx/cti.png), then choose your connected Snom phone from the list.

   ![Drop-down list for selecting a connected Snom phone to control in CTI mode](/images/pbx/snom-cti-mode-web-1.png)

## What you can control

With the Snom phone connected, the web client lets you handle its calls in these ways:

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