| Name | Type | Description | Notes |
|---|---|---|---|
| phone_number | string | Phone number for receiving Voice PreAlertNotification. Valid values are 0 - 9. If the country or territory of the message recipient is US, PR, CA, and VI, the layout is: 1, area code, 7 digit phone number or 1, area code, 7 digit phone number, 4 digit extension number. For other countries or territories, the layout is country or territory code, area code, 7 digit number. |