Microsoft touts Office Communications Server (OCS), the successor to Live Communications Server (LCS), as the cornerstone of its unified communications solution, but OCS targets enterprise-level organizations. Although pricing for OCS is not yet available, LCS costs $1,199 for the Standard Edition with five client-access licenses (CALs) or $4,969 for the Enterprise Edition with 25 CALs. That’s beyond the budget of many small businesses.

OCS works in conjunction with Microsoft Exchange 2007. However, Exchange alone can provide basic unified messaging features for smaller businesses without the complexity and cost of deploying OCS.

Let’s take a look at some of the benefits you can derive from using Exchange 2007 for e-mail services.

Exchange goes unified

Exchange 2007 was the first version of Microsoft’s e-mail server to introduce the concept of unified messaging as an integral feature. This is almost a necessity in today’s business world, as various types of communications — e-mail messages, faxes, phone calls, etc. — constantly inundate workers, who don’t have the time or the inclination to deal with half a dozen separate devices or applications to receive and organize all the incoming data.

Of course, unified messaging has been a progressive thing. Exchange 2003 allowed mobile users to access their inboxes remotely to get their e-mail and calendar information.

But the next step in unified communications does much more. Microsoft calls it “the third wave of unified messaging technology.” Now users can access their voice mail messages and faxes from that same inbox.

But it’s not only about having different types of messages accessible in the same place. It’s also about being able to access that “same place” no matter where you might be, using your choice of devices.

Outlook 2007 works seamlessly with Exchange 2007 for receiving, sorting, and searching voice mail messages as well as e-mail. However, you don’t have to be at your desktop computer running Outlook to get your messages now. You can also access them from any Internet-connected computer via Outlook Web access, from your mobile device (PDA or cell phone), or even by calling in from a standard telephone.

Exchange 2007’s modular architecture

Exchange 2007 consists of five different server roles.

  • The Edge Transport Server
  • The Hub Transport Server
  • The Mailbox Server
  • The Client Access Server
  • The Unified Messaging Server

The Edge Transport Server resides in a perimeter network, but you can run the other server roles on separate machines, or you can put them all on the same physical server.

The Hub Transport Server is the piece that moves messages between the other servers. The Mailbox Server, as the name implies, holds the user mailboxes that store messages (e-mail, fax, and voice mail). The Client Access Server facilitates communication between the mailboxes and client software (i.e., Outlook, OWA, ActiveSync).

The Unified Messaging Server component of Exchange 2007 is what makes it possible for the Exchange server to store faxes and voice mail messages and interoperate with the organization’s PBX (including multiple PBXs). It provides communication between the telephony system and the e-mail system. The Unified Messaging Server supports both VoIP and legacy PBX systems using a VoIP gateway. (Intel and other companies manufacture compatible gateways.)

The Unified Messaging Server also provides for an Automated Attendant service. This service can answer phone calls — both internal and external — and can use the Global Address List (GAL) for automated dialing. It can route calls to specific users or based on roles or departments as defined in Active Directory.

Finally, these services include Outlook Voice Access (OVA). This lets you call in from any phone and have your e-mail, directory information, appointments, and contact information read to you via text-to-speech functionality. You can also update your calendar over the phone.

How it works

The Unified Messaging Server uses the industry-standard Session Initiation Protocol (SIP) to establish communications with the IP-PBX or the VoIP gateway. It uses the Real-Time Protocol (RTP) for sending the actual voice traffic.

The server records voice messages using the audio codec that the administrator designates. The default codec is Windows Media (WMA), which Windows Media Player can play. The server attaches the audio file to a MIME SMTP message and delivers it to the recipient’s mailbox. The server uses the T.38 protocol to send faxes, and it sends it to the user’s mailbox as a .tiff image.

When a user calls in to access messages via OVA, the call goes from the PBX to the server. The user must enter a PIN (stored in the user’s Active Directory account in encrypted form, which the user can change via OWA or OVA). This protects the mailboxes from unauthorized access over the phone. The user uses simple commands, such as “voice mail” or “e-mail” and then commands such as “next message,” “forward,” “reply,” and so forth to manage the playback and response to messages.

Benefits to users, IT, and the company

Using Exchange 2007’s unified messaging features provides benefits on many levels:

  • Users benefit from the convenience of having their communications available in one centralized place, accessible in a number of ways. This saves them time and makes it easier for them to organize the information.
  • IT benefits from easier management of communications in a centralized location, rather than having to deal with multiple servers handling different types of messages. It’s also easier to back up and secure the data when it’s in a centralized location.
  • The company benefits from cost savings realized by consolidating servers (lower hardware costs) and increased productivity on the part of workers.
  • Even persons outside the company benefit. For instance, the Automated Attendant can route external callers to the correct recipient more quickly and easily.


You don’t have to be an enterprise-level company that can afford to deploy Office Communications Server to get many of the benefits of unified communications within a Microsoft infrastructure. Exchange 2007’s unified messaging features can put you well on the way without the extra cost. And when your organization has grown to the point where you can afford OCS, Exchange 2007 works together with it to give you more advanced UC capabilities.

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