# Set up Contact Synchronization from Zendesk

Once Cloud Voice is connected to Zendesk, you can have your Zendesk contacts copied into a Cloud Voice phonebook automatically. This is a one-directional sync: records move from Zendesk into Cloud Voice, and the resulting phonebook is read-only.

## Before you begin

Make sure you have already [integrated Cloud Voice with Zendesk](/pbx/integrations/zendesk/integrate-cloud-voice-with-zendesk/).

## Turn on synchronization

1. Sign in to the PBX (Private Branch Exchange, your phone system) web portal and open **Integrations > Helpdesk**.
2. On the Zendesk integration page, switch on **Synchronize Contacts Automatically**.
3. Use the **Synchronize to Phonebook** drop-down to choose where the contacts should land. Pick an existing empty phonebook, or create a new one for this purpose.

   :::note
   Contacts can be synced only into a phonebook that is empty.
   :::

   ![Selecting the destination phonebook for synchronized Zendesk contacts](/images/pbx/sync-to-zendesk-phonebook.png)

4. Decide how you want the **Always Query Helpdesk** option set. This controls whether Cloud Voice looks up contact details in Zendesk in real time.

   
   ![Cloud Voice, the Always Query Helpdesk toggle on the integration page](/images/pbx/always-query-helpdesk.png)

   - **Enabled:** Cloud Voice queries Zendesk on every lookup, and extension users can search Zendesk contacts as they dial from the Cloud Voice App.
   - **Disabled:** Cloud Voice only reaches out to Zendesk when no match is found in your company contacts.

   :::caution
   - Real-time lookups consume more API (Application Programming Interface) calls, so keep an eye on your Zendesk API quota.
   - Real-time search does not work while number masking is turned on.
   :::

5. Click **Save**.

## What you get

In **Contacts > Phonebooks**, the linked phonebook is marked with a helpdesk label.

![The synchronized phonebook tagged with a helpdesk label in the phonebook list](/images/pbx/help-desk-label.png)

![The Zendesk-linked phonebook populated with synchronized contacts](/images/pbx/zendesk-phonebook.png)

From then on, whenever the linked extension takes an inbound call from a Zendesk contact or dials one, the matching contact record is pulled into the Cloud Voice phonebook automatically.

:::note
Because the sync only runs from Zendesk to Cloud Voice, the linked phonebook and every contact in it are read-only.
:::

## Some contacts won't sync

Records with missing details can fail to synchronize. Confirm that each contact has the following, then run the directory sync again:

- A value in either the **First name** or the **Last name** field.
- At least one phone-number field filled in.