Call answering is the receiving of voice messages on behalf of users whose calls are not answered or are busy. It includes playing a personal greeting, recording a message, and submitting the message to be queued for delivery to the user's mailbox, which is stored on the Exchange mailbox server.

If a caller leaves a message, the message is routed to the user's Inbox. If a caller chooses not to leave a message, a missed call notification is stored in the user's mailbox. Users can then access their Inbox by using the Microsoft Outlook messaging and collaboration client, Outlook Web Access, the Exchange ActiveSync technology, or Outlook Voice Access. The subject and priority of calls can be displayed in a way similar to that of email.

Outlook Voice Access enables an Enterprise Voice user to access not just voice mail, but also the Exchange inbox, including email, calendar, and contacts from a telephony interface. The subscriber access number is assigned by an Exchange UM administrator.

Auto attendant is an Exchange UM feature that can be used to configure a phone number that outside users can dial to reach company representatives. In particular, it provides a series of voice prompts that assist an external caller in navigating a menu system. The list of available options is configured on the Exchange UM server by the Exchange UM administrator.

Exchange UM includes fax features, which enable users to receive incoming faxes in their Exchange mailboxes. For details, see "Unified Messaging" in the Microsoft Exchange Server documentation at http://go.microsoft.com/fwlink/p/?linkId=135652.

Note:
Fax services provided by the Exchange UM server are not available in Lync Server deployments that are integrated with Microsoft Exchange Server 2010, Exchange 2010 with the latest service pack, or Exchange 2013.