Open Communications Server Control Panel.

In the left navigation bar, click Voice Features.

Click the Unassigned Number tab.

On the Unassigned Number page, click New.

In the New Unassigned Number Range dialog box, in the Name field, type the name for this range of numbers.

In the first Number range field, type the first number in the range of numbers. The value must be less than or equal to the value specified in the second Number range field, which specifies the last number in the range of numbers.

Note:
The number must match the regular expression (tel:)?(\+)?[1-9]\d{0,17}(;ext=[1-9]\d{0,9})?. This means the number may begin with the string tel: (if you don’t specify that string it will be automatically added for you), a plus sign (+), and a digit 1 through 9. The phone number can be up to 17 digits and may be followed by an extension in the format ;ext= followed by the extension number.

In the second Number range field, type the last number in the range of numbers.

Note:

The value must be greater than or equal to the number specified as the first number in the range. The number must match the regular expression (tel:)?(\+)?[1-9]\d{0,17}(;ext=[1-9]\d{0,9})?. This means the number may begin with the string tel: (if you don’t specify that string it will be automatically added for you), a plus sign (+), and a digit 1 through 9. The phone number can be up to 17 digits and may be followed by an extension in the format ;ext= followed by the extension number.

In the FQDN of destination server field, do one of the following:

• Click Announcement.
  
  
• Click Exchange UM.
  
  

If, in the previous step, you clicked Announcement, do the following:

1. Click Announcement service, click Select, select the service ID of the Application service that runs the Announcement application that will handle incoming calls to this range of unassigned numbers, and then click OK.
   
   
2. In the Announcement field, select the announcement that will be played for this range of unassigned numbers.
   
   

If, in the previous step, you clicked Exchange UM, click Auto Attendant phone number, click Select, select the phone number that will be used for this range of unassigned numbers, and then click OK.

Click OK.

On the Unassigned Number page, make sure that the unassigned number ranges are arranged in the order you want. To change a range's position in the table, highlight the range in the list and then click the up or down arrow.

Tip:
Communications Server 2010 searches the unassigned number table from top to bottom and uses the first range that matches the unassigned number. If you have a range that specifies a last resort action, make sure that range is at the bottom of the list.