To create a new UM dial plan, in the New UM Dial Plan wizard, on the New UM Dial Plan page, complete the following information:

Name

• A UM dial plan name is required and must be unique. However, it is used only for display in the Exchange Management Console and the Exchange Management Shell. If you have to change the display name of the dial plan after it has been created, you must first delete the existing UM dial plan and then create another dial plan that has the appropriate name. If your organization uses multiple UM dial plans, we recommend that you use meaningful names for your UM dial plans. The maximum length of a UM dial plan is 64 characters, and it can include spaces. However, it cannot include any of the following characters: " / \ [ ] : ; | = , + * ? < >.
  
  

Number of digits in extension numbers

• The number of digits for extension numbers is based on the telephony dial plan that is created on a PBX. For example, if a user associated with a telephony dial plan dials a 4-digit extension to call another user in the same telephony dial plan. You select 4 as the number of digits in the extension. This is a required field that has a value range from 1 to 20. The typical extension length is from 3 to 7. If your existing telephony environment includes extension numbers, you must specify a number of digits that matches the number of digits in those extensions.
  
  
• When you create a SIP or E.164 dial plan and associate a UM-enabled user with the dial plan, you must still input an extension number to be used by the user. This number is used by an Outlook Voice Access user when they access their Exchange 2007 mailbox.
  
  

URI Type 

• Use this drop-down list to select the URI type for the UM dial plan.
  
  
• A Uniform Resource Identifier (URI) is a string of characters that identifies or names a resource. The main purpose of this identification is to enable VoIP devices to communicate with other devices over a network by using specific protocols. URIs are defined in schemes that in turn define a specific syntax, format, and the protocols for the call.
  
  
• You can select one of the following URI types for the dial plan:
  
  
  • Telephone extension   This is the most common URI type. The calling and called party information from the IP gateway or IP PBX will be listed in one of the following formats: Tel:512345 or 512345@<IP address>. This is the default URI type for dial plans.
    
    
  • SIP URI   Use this URI type if you need a SIP URI dial plan when an IP PBX supports SIP routing or if you are integrating Office Communications Server 2007 and Exchange Unified Messaging. The calling and called party information from the IP gateway or IP PBX will be listed as a SIP address in the following format: sip:<username>@<domain or IP address>:Port.
    
    
  • E.164   E.164 is an international numbering plan for public telephone systems in which each assigned number contains a country/region code (CC), a national destination code (NDC), and a subscriber number (SN). The calling and called party information that is sent from the IP gateway is listed in the following format: Tel:+14255551234.
    
    
• After you create a dial plan, you will be unable to change the URI type without deleting the dial plan, and then re-creating the dial plan to include the correct URI type.
  
  

VoIP Security 

• Use this drop-down list to select the VoIP security setting for the UM dial plan. By default, when you create a UM dial plan, it will communicate in Unsecured mode.
  
  
• You can select one of the following security settings for the dial plan:
  
  
  • Unsecured   By default, when you create a UM dial plan, it will communicate in Unsecured mode and the Unified Messaging servers that are associated with the UM dial plan will send and receive data from IP gateways, IP PBXs, and other Exchange 2007 computers by using no encryption. In Unsecured mode, both the Realtime Transport Protocol (RTP) media channel and SIP signaling information will not be encrypted.
    
    
  • SIP secured   When you select SIP secured, only the SIP signaling traffic will be encrypted and the RTP media channels will still use Transmission Control Protocol (TCP), which is not encrypted. Mutual Transport Layer Security (MTLS) is used to encrypt the SIP signaling traffic.
    
    
  • Secured    When you select Secured, both the SIP signaling traffic and the RTP media channels are encrypted. An encrypted signaling media channel that uses Secure Realtime Transport Protocol (SRTP) also uses MTLS to encrypt the VoIP data.
    
    
• A Unified Messaging server can operate in any mode that is configured on a dial plan because the Unified Messaging server is configured to listen on TCP port 5060 for unsecured requests and on TCP port 5061 for secured requests at the same time.
  
  

After you complete the fields on the New UM Dial Plan page of the New UM Dial Plan wizard, click New to create the new UM dial plan.

For more information about UM dial plans, see the following topics:

• Managing Unified Messaging Dial Plans
  
  
• Understanding Unified Messaging Dial Plans
  
  

For more information about dial plan security, see Understanding Unified Messaging VoIP Security.