[This is pre-release documentation and subject to change in future releases. This topic's current status is: Milestone-Ready]

Topic Last Modified: 2010-07-14

In Microsoft Communications Server 2010, you can specify what happens to incoming calls to phone numbers that are valid for your organization but are not assigned to a user or phone. Callers can hear a message or be routed to another destination or both.

How you configure the unassigned number table depends on how you want to use it. You can configure the table with all the valid extensions for your organization, with only unassigned extensions, or with a combination of both types of numbers. The unassigned number table can include both assigned and unassigned numbers, but it is invoked only when a caller dials a number that is not currently assigned. If you include all the valid extensions in the unassigned number table, you can specify the action that occurs whenever someone leaves your organization, without needing to reconfigure the table. If you include unassigned extensions in the table, you can tailor the action that occurs for specific numbers. For example, if you change the extension for your customer service desk, you can include the old customer service number in the table and assign it to an announcement that provides the new number.

Before you configure the unassigned number table, your system must already either have Announcements defined or an Exchange Unified Messaging (UM) Auto Attendant set up.
When someone calls an unassigned number, Communications Server searches the unassigned number table from top to bottom and uses the first matching range. Therefore, an action that you want to be performed as a last resort should be specified for the last range in the table.

In This Section