# Initiate an outbound call

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Zoom supports various URI schemes that enable you to click a secure hyperlink or a button that launches the Zoom
Phone client.

![](/img/1608770412973.png)

This guide provides you with an overview of the supported URI
schemes you can use to redirect your app users to the Zoom Phone
client to make outbound calls.

## Prerequisites

To use these schemes, the caller must meet the following
prerequisites:

-   Install the [latest version](https://zoom.us/download) of Zoom client and stay logged in before initiating a call from another app.
-   Have a valid [Zoom Phone number](https://support.zoom.us/hc/en-us/articles/360028936531-Getting-started-with-Zoom-Phone-users-).

## Supported URI schemes

Zoom supports these URI schemes to launch the Zoom Phone client and place calls.

-   `callto`
-   `tel`
-   `zoomphonecall`

> **Notes**:
>
> -   Basic `zoomphonecall` URI support to exclude iOS `callerid` and `seccall` parameters.
> -   No `zoomphonecall` and `tel` support for Android due to the system security limitations.

### `callto` and `tel` URI schemes

The `callto` and `tel` URI schemes are popular industry standard schemes. You can use either of these schemes to launch the Zoom Phone client.

Implement the `callto` scheme with the following URL format:

-   `callto:{phoneNumberToCall}`
-   Example: `callto:+123456789`

Implement the `tel` scheme with the following URL format:

-   `tel:{phoneNumberToCall}`
-   Example: `tel:+123456789`

### `zoomphonecall` URI scheme

You can use the `zoomphonecall` scheme to make calls.

#### The `callerid` parameter

You can change how the user's default caller ID displays using this parameter. The `zoomphonecall://{1234567}?callerid={10001}` calls out with 10001 as the caller ID, although it is actually 20002. For example, note that the caller ID has to be an extension or an E.164 number. Use of this parameter does not change the default caller ID in the Zoom Phone client.

#### CLI examples

Use these examples to test or integrate URI schemes using the command line.

```shell
Zoom --url="zoomphonecall://+15551234567"
Zoom --url="zoomphonecall://+15551234567?callerid=+15557654321"
Zoom --url="zoomphonecall://+15551234567?cat=report&bind=abc123"
Zoom --url="zoomphonesms://+15551234567?callerid=+15557654321"
```

#### Autodial

Upon successful execution of `zoomphonecall://{phoneNumbertoCall}`, the Zoom client launches and auto-dials the number.