It's challenging to create guidelines for deploying telephony networks. They can be very different from one another because they can include VoIP gateways, IP PBXs, and PBXs with different configuration settings, firmware, and requirements. However, several resources are available to help you successfully deploy Unified Messaging:

• Unified Messaging specialists   UM specialists are systems integrators who have received technical training about Exchange Unified Messaging conducted by the Exchange engineering team. To help ensure a smooth transition to Unified Messaging from legacy voice mail systems, Microsoft recommends that all customers engage a UM specialist. For contact information, visit Microsoft Exchange Server 2013 Unified Messaging (UM) Specialists or Microsoft Pinpoint for Unified Messaging.
  
  
• Configuration Notes for Supported VoIP Gateways, IP PBXs and PBXs   These configuration notes contain settings and other information that's very useful when you're configuring VoIP gateways, IP PBXs, and PBXs to communicate with the Unified Messaging servers that are on your network. For more information, see Configuration Notes for Supported VoIP Gateways, IP PBXs, and PBXs.
  
  
• Configuration Notes for Supported Session Border Controllers   These configuration notes contain settings and other information that's very useful when you're configuring session border controllers (SBCs) to communicate with the Unified Messaging servers in hybrid and Exchange Online UM deployments. For more information, see Configuration Notes for Supported Session Border Controllers.
  
  

Before you engage a Unified Messaging specialist, you should be able to answer key questions that they'll ask. Having the answers to the following questions will help make the conversation between you and the UM specialist productive:

• How many existing telephone or voice mail users, or both, are in your organization?
  
  
• How many users do you intend to provide with Unified Messaging?
  
  
• Which PBX or PBXs do you intend to use for integration with Unified Messaging?
  
  
• How many PBXs does your organization have? Specify the vendors, types (circuit- or IP-based), models, and firmware versions.
  
  
• Are the PBXs networked, and are they centralized or located in multiple locations?
  
  
• What voice mail system or systems does your organization currently use? Specify the vendors, types, models, and firmware versions.
  
  
• How are the voice mail systems integrated into your PBXs (Analog, T1/E1, PRI, Digital set emulation, VoIP, other)?
  
  
• Are you currently using voice networking?
  
  
• What type of fax system or systems does your organization use, and does the fax system or systems support inbound fax routing to Exchange?
  
  
• Does your organization use automated attendants?
  
  
• Do you need support for phone-only users, that is, users who won't have email access?
  
  

Integrating Unified Messaging with PBXs requires you to use one or more VoIP gateways to translate the circuit-switched protocols that are used by TDM-based PBXs to IP-based, packet-switched protocols that are used by Unified Messaging. VoIP gateway vendors with several models of VoIP and media gateways have been tested and are supported for Unified Messaging.

Interoperability testing of Unified Messaging with VoIP gateways, IP PBXs, and SBCs is now integrated with the Microsoft Unified Communications Open Interoperability Program. For more information, see Microsoft Unified Communications Open Interoperability Program.

The Microsoft Unified Communications Open Interoperability Program qualification program for VoIP gateways, IP PBXs, and advanced VoIP gateways ensures that customers have a seamless setup and support experience when they're using qualified telephony VoIP gateways and IP PBXs with Microsoft Unified Communications software. Only products that meet rigorous and extensive testing requirements and conform to the specifications and test plans receive qualification.

For details about configuring supported VoIP gateways, IP PBXs, PBXs, and SBCs, see one of the following resources:

• Configuration Notes for Supported VoIP Gateways, IP PBXs, and PBXs
  
  
• Configuration Notes for Supported Session Border Controllers
  
  

Interoperability was verified for the following VoIP gateway vendors:

• AudioCodes
  
  
• Dialogic
  
  
• The following table shows the VoIP gateway vendor, the VoIP gateway model, and the protocols that are supported by each model.
  
  

Supported VoIP gateways for Unified Messaging

The following table shows the PBXs that are supported using AudioCodes VoIP gateways, including MediaPack-114 FXO, MediaPack-118 FXO, and Mediant 2000.

PBXs supported with an AudioCodes VoIP gateway

Each Dialogic VoIP gateway model supports different PBXs. The following tables show the PBX manufacturer and model and which Dialogic VoIP gateway can be used. Each VoIP gateway uses different signaling methods, densities, and protocols.

PBXs supported when using a DMG1000 series Media Gateway

PBXs supported when using a DMG 2000 series Media Gateway

PBXs supported when using a DMG4008BRI series Media Gateway

IP PBXs are also supported by Unified Messaging. The following table shows the IP PBXs that are supported using a direct SIP connection to Unified Messaging.

IP PBXs supported when using a direct SIP connection

IP PBXs using SIP media gateways are also supported by Unified Messaging. The following table shows the IP PBXs that are supported using IP to IP capabilities of SIP media gateways to connect to Unified Messaging.

IP PBXs supported when using a SIP media gateway

For on-premises and hybrid deployments, Exchange Unified Messaging can be deployed together with Microsoft Office Communications Server 2007 R2, Microsoft Lync Server 2010 or Lync Server 2013 to provide voice messaging, Instant Messaging (IM), enhanced user presence, audio-video conferencing, and an integrated email and messaging experience for users in your organization. For more information, see:

• Integrate Exchange 2013 UM with Lync Server
  
  
• Microsoft Lync Server 2013
  
  

To find out more about the Microsoft Unified Communications Open Interoperability Program for enterprise telephony infrastructure, including finding qualified SIP PSTN gateways and IP PBXs and the process for telephony infrastructure vendors to join and participate in the program, see Microsoft Unified Communications Open Interoperability Program.