When an Exchange 2010 Unified Messaging server records the audio for a voice mail message, it uses ASR to create voice mail preview text from the audio file, and then submits the whole voice message to a Hub Transport server for delivery to the user. For each voice message that's created, a Unified Messaging server determines a confidence level for the voice mail preview included with the message. The voice mail system measures how well the sounds in the recording match the words, numbers, and phrases. If the system finds matches easily, the confidence level will be high. A higher level of confidence is generally associated with a higher accuracy.

The accuracy of Voice Mail Preview text is controlled by many factors, and sometimes those factors can't be controlled. However, the text is likely to be more accurate when:

• A simple voice mail is left, and the caller doesn't use slang terms, technical jargon, or unusual words or phrases.
  
  
• The caller uses a language that's easily recognized and translated by the voice mail system. Generally, voice messages left by callers who don't speak too quickly or too softly and who don't have strong accents will produce more accurate sentences and phrases.
  
  
• The voice message is free of background noise, echoes, and the audio doesn't drop out.
  
  

Most customers who deploy Exchange 2010 Unified Messaging find that the voice mail previews are accurate enough for their users. However, when ASR is applied to recordings made over the phone by unknown voices and background noises, the voice mail preview text usually isn't completely accurate. If the level of confidence is consistently low or the voice mail previews that are received aren't very accurate, you can increase the accuracy of the Voice Mail Previews that users receive as follows:

• Sign up for a voice transcription service from a Voice Mail Preview partner. For more information about where to find a Voice Mail Preview partner, see the section "Voice Mail Preview Partners Certified for Exchange 2010 Unified Messaging" later in this topic.
  
  
• After you've signed up with a Voice Mail Preview partner, use the information provided by the partner to set it up to work with Unified Messaging. For more information, about how to configure UM for a Voice Mail Preview partner, see Configure a Voice Mail Preview Partner on a UM Mailbox Policy.
  
  

When you've signed up with a Voice Mail Preview partner, the UM server redirects voice mail messages with the audio file attached to a Voice Mail Preview partner instead of generating Voice Mail Preview text for voice messages and submitting the voice messages to a Hub Transport server. The e-mail message with the Voice Mail Preview text produced by the Voice Mail Preview partner is then submitted to the Hub Transport server for delivery to the recipient's mailbox.

Important:

We recommend that all customers who plan to deploy Unified Messaging obtain the assistance of a Unified Messaging specialist. A Unified Messaging specialist helps you ensure that there's a smooth transition to Exchange 2010 Unified Messaging from a legacy voice mail system. Performing a new deployment or upgrading a legacy voice mail system requires significant knowledge about PBXs and Exchange 2010 Unified Messaging. For more information about how to contact a Unified Messaging specialist, see the Microsoft Exchange Server 2007 Unified Messaging (UM) Specialists Web site.

To become certified as a Voice Mail Preview partner that interoperates with Exchange 2010 UM, the partner must implement the requirements contained in the Voice Mail Preview Interoperability Specification, and the partner solution must be certified by an independent certification vendor. If you're interested in certifying your transcription service to work with Exchange 2010 Unified Messaging, submit a request to Voice Mail Preview Partners for Exchange 2010 Unified Messaging.

If you've already deployed Exchange 2010 Unified Messaging in your organization and you're looking for a certified Voice Mail Preview partner to provide transcription support services, see Independent Software Vendors. These software vendors have been certified as interoperable with Exchange Server 2010.

The Exchange 2010 UM server forwards voice mail message with the audio to a dedicated Voice Mail Preview partner solution, which then takes the audio file and creates the Voice Mail Preview text. However, to allow UM-enabled users to receive the Voice Mail Preview with their voice mail message in their mailbox, you must configure a UM mailbox policy, associate users with the UM mailbox policy, and then have the UM-enabled users verify that they can receive voice mail previews in their voice mail messages in Outlook 2010 or Outlook Web App. For more information about Voice Mail Preview with Outlook 2010 and Outlook Web App, see Outlook 2010 and Outlook Web App Features in Unified Messaging. For more information, about how to configure UM for a Voice Mail Preview partner, see Configure a Voice Mail Preview Partner on a UM Mailbox Policy.

Configuring IP gateways and IP PBXs for your organization is a difficult deployment task that must be completed correctly to successfully deploy Exchange 2010 Unified Messaging with a Voice Mail Preview partner. For information that can help you configure your IP gateways and IP PBXs and for the most up-to-date information about how to configure them, see Telephony Advisor for Exchange 2010.

Testing interoperability of Exchange 2010 Unified Messaging with IP gateways has been integrated with the Office Unified Communications Open Interoperability Program. For more information, see Microsoft Unified Communications Open Interoperability Program.