SolutionBase: An overview of Unified Messaging in Exchange Server 2007

Users need more than e-mail to keep in touch with the outside world; they need access to phones and faxes as well. Brien Posey shows how Exchange 2007 handles the problem of bringing messaging together.

This article is also available as a TechRepublic download.

Of all its new features, Exchange Server 2007 is best known for Unified Messaging (UM), a new role that allows users to receive e-mail, voicemail, and faxes in their inbox. In this article, I will discuss how UM works, as well as its capabilities and limitations.

Why use UM?

Before I get started with the technical portion of this article, I want to talk for a moment about how UM can benefit your organization. If you really stop and think about it, the way a typical information worker works is terribly inefficient. According to a study by Gartner, seven out of 10 phone calls go directly to voicemail. Consequently, when a user returns to their desk, they would typically open Outlook to check e-mail, and then use their phone to check voicemail. If the user was expecting a fax, they may also have to walk over to the fax machine to see if the fax has arrived yet. Users waste a lot of time checking messages, because each of these three different types of messages must be checked in a different way.

When a user is working outside of the office, the inefficiencies are compounded. Assuming that the user has a mail-enabled PDA, checking e-mail is not a big deal. E-mail messages are typically sent directly to the PDA using ActiveSync. Checking voicemail is a different story, however. Even if the user is using a PDA/cell phone hybrid, the user typically has to dial into the office voicemail system to check their messages at the office. If the user is expecting a fax, they may even have to make a phone call to a co-worker to find out if the fax has arrived.

UM allows voice and fax messages to be placed directly into a user's inbox so these messages can be viewed right alongside e-mail. What makes this technology even more enticing is that UM works with Outlook 2007, Outlook Web Access (OWA), and a brand new component called Outlook Voice Access (OVA).

How does UM integrate into an existing Exchange organization?

Typically, an Exchange Server organization is completely separate from a company's telephone system. So, how it is even possible for Exchange Server to handle voicemail and faxes?

Exchange 2007 is designed to make use of VoIP technology. IP is the same protocol used by Exchange Server and virtually every other type of modern server. If the company has deployed a compatible IP-based PBX system, then no additional hardware will be needed. Companies relying on traditional PBX systems will simply need to deploy a VoIP Gateway. This Gateway will serve as a bridge between the Exchange Server organization and the PBX system. VoIP gateways tend to be relatively inexpensive.


The basic architecture used by UM provides a couple of other benefits as well. The first of these benefits is the central management of voicemail. For smaller companies that operate out of a single building, this probably isn't a big deal. For larger companies with multiple facilities, however, being able to centrally manage a voicemail system is almost unheard of.

Imagine the company you work for has acquired another company. Both companies will probably already have some form of voicemail hardware in place. However, the odds of the two companies using identical hardware are pretty slim. Under normal circumstances, this would mean whoever is in charge of administering the voicemail system would have to learn the particulars of both systems. If both companies are relatively large, you may even need to have separate voicemail administrators at each facility.

With UM in place, things get a little bit simpler. Assuming your Exchange Server organization spans multiple sites (you have Exchange Servers in each facility), then half of the work is already done. All you have to do is to deploy the UM role on an Exchange Server in each facility. UM works best on a dedicated server, but that is not an absolute requirement in smaller organizations. Once the UM role has been deployed, you must link the UM server to the facility's PBX server, either directly or through a VoIP Gateway.

The end result is that the voicemail hardware and Exchange Servers are still distributed throughout your organization. However, the entire pool of UM servers communicate with the Active Directory, which can be centrally managed.

The other side effect to the UM infrastructure is that voice messages and faxes can be treated like e-mail messages. More specifically, this means you can perform nightly backups that include voicemails and faxes. You also have the ability to archive voice messages and faxes in the same way you would archive e-mail messages.

Long term archival of voice messages and faxes presents some interesting problems. For example, when e-mails are archived, the archives are sometimes searched for messages from a specific person or pertaining to a specific subject.

Normally, voice messages would not contain sender information or subject information; however, Microsoft has created a couple of mechanisms that allow voice messages to be searched in the same way e-mail messages are.

Once a voicemail arrives, the caller ID information is bound to the message. This caller ID information only references the caller's phone number, not their name. However, Exchange Server searches the Active Directory for the phone number to see if they can identify the caller by name. If the Active Directory does not contain a record for the caller, then the recipient's contacts are searched for a match. If the recipient's personal contacts contain a record with a matching phone number, then the caller's name is inserted into the message.

Unfortunately, Exchange 2007 doesn't make an effort to automatically index the contents of a voice message. However, speech recognition technology has progressed so rapidly that it would not surprise me if the next version of Exchange Server was able to automatically index voice messages. For now, Microsoft allows users to take notes regarding the contents of a voice message. These notes are stored along with the message so the user can search for the message later on if needed.


Inbound faxes present their own set of challenges for UM. The main problem with faxes is that there are a number of different ways in which a fax can be received. Ideally, each user would have their own individual fax number linked to the company's PBX system. In a situation like this, Exchange Server could easily be set up so it knows faxes coming in on a particular phone line need to be routed to a specific user's inbox. In the real world, this type of configuration is often cost prohibitive.

As an alternative, some voicemail systems — such as the one that I use — support voice and fax on the same line. When someone calls the phone number and the voicemail answers, it plays a normal greeting that it gives the caller a chance to leave a message. At the same time, the system is listening for a tone generated by a fax machine. If the voicemail system hears such a tone while the greeting is being played, then it knows the incoming call is a fax and immediately switches to fax mode.

From an UM perspective, this type of system works as well as having a dedicated fax line for each user. Since each user already has their own voicemail box, there is a one-to-one relationship between phone numbers and users. Therefore, UM can be configured so it knows faxes coming in on a specific phone line need to be routed directly to a designated user.

Some companies tend to be a bit more limited on resources; a single fax line is shared by everyone in the office. This presents a bit of a problem for Exchange Server because faxes coming into this line could potentially be intended for any of the users. Fax machines have been around for a couple of decades, and tend to be rather simplistic in nature. There is no signal embedded in a fax that designates recipient information in a way that Exchange Server can understand.

If multiple users share a fax line, faxes must be manually routed. Typically, inbound faxes arriving on a shared line would be placed into an administrative mailbox, and it would be up to an administrative assistant to manually forward the fax to the designated recipient. Although manual intervention is required, Exchange Server assists in a surprising way.

When faxes arrive, Exchange Server performs optical character recognition on the first page of the fax to try to determine the name of the recipient. If optical character recognition does not yield any useful data, then Exchange Server attempts to use handwriting recognition to determine the recipient's name.

The person who has been designated to forward faxes to the recipient does not forward faxes in the same manner that e-mail messages would be forwarded. Instead, they use a mechanism called the Fax Reception Assistant. This assistant displays the name of the intended recipient, as well as a confidence level that shows how confident Exchange Server is that it has correctly identified the recipient.

The person responsible for managing inbound faxes can either click a forward button to immediately forward the fax to the intended recipient, or a preview button to preview the fax before forwarding it on. This is helpful when Exchange Server has low confidence that it has correctly identified the fax recipient.

Outlook Voice Access

As I mentioned at the beginning of this article, the primary benefit of UM is that e-mail, voicemail, and faxes are all stored in a user's inbox. Users can access all three message types through Outlook 2007, OWA, or OVA. OVA is a new user interface that allows users to interact with their mailbox using a telephone.

OVA is primarily designed to work with a user's inbox and calendar. For example, a user can dial the OVA phone number and verbally request that their e-mail be read to them over the phone. A text-to-speech engine will then verbally read the messages to the user. The user can even reply to messages over the phone (replies are stored as attached audio files). Users can also use simple verbal commands to forward or delete messages, and can perform most other message-related tasks that they would normally be able to do through Outlook.

OVA's calendar features work similarly. If users are running late for a meeting, they could dial into OVA and tell the interface they are running fifteen minutes late for a meeting. They also have the option of verbally providing an explanation of why they are running late. The other designated meeting attendees are automatically informed of the meeting's new time. If the user has provided an explanation, then that explanation is attached to the message as an audio file.

Exchange 2007 unifies messaging

As you can see, Exchange 2007 integrates itself into your existing phone system with relative ease. UM does have a few shortcomings, but is mostly a good solution for integrating various forms of communications within your office.

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