# Control a Snom IP Phone with the Cloud Voice App Desktop Client

CTI (Computer Telephony Integration) mode lets the Cloud Voice App desktop client pair with a Snom deskphone that has your extension registered on it. Once paired, the app becomes an on-screen control panel for call handling, while the audio path stays on the Snom phone, you place, answer, and manage calls from your computer, and speak through the deskphone.

## Where this applies

Use these steps with any Snom model listed among the [phones supported for Cloud Voice App desktop CTI](/pbx/desktop-client-user-guide/cloud-voice-app-desktop-client-cti-overview/#linkus-web-client-cti__table_vz3_dl5_tzb).

:::tip
Using a deskphone that isn't on the supported list? See [Control an Incompatible IP Phone with the Cloud Voice App Desktop Client](/pbx/desktop-client-user-guide/remotely-control-an-incompatible-ip-phone-by-cloud-voice-app-desktop-client/) instead.
:::

## Before you start

Confirm the following with your system administrator:

- The PBX (Private Branch Exchange, the phone system that routes your calls) server is running version `84.13.0.25` or later.
- The **uaCSTA** feature is turned on, under **PBX Settings > SIP Settings > Advanced > Other Options > Enable uaCSTA Connection**. uaCSTA (user-agent CSTA, or Computer-Supported Telecommunications Applications) is the standard that lets the app control the deskphone.

On the deskphone itself, the extension registered must match the extension you sign in with on the Cloud Voice App desktop client.

:::caution
Register only one account on the Snom phone. Additional accounts can prevent CTI control from working.
:::

## Step 1. Make the deskphone controllable

:::note
If your administrator pushed your extension to the phone through Auto Provisioning, the phone is already set up for control. 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, turn on CSTA control on the phone first. The steps below use a Snom D735 as an example:

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

   ![Snom web interface Security settings with Allow CSTA Control enabled](/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 Cloud Voice App

Switch the desktop client into CTI mode to start managing calls on the deskphone:

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

   ![CTI mode drop-down showing the connected Snom phone selected](/images/pbx/snom-cti-mode-pc-1.png)

## What you can do next

With the Snom phone connected, the following actions are available from the Cloud Voice App desktop client:

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