Integrating Communications Server 2007 R2 with Exchange UM When a User’s Mobile Number Is Their Primary Number

many organizations, users have a mobile phone as their work phone and
private phone. As an example, many companies in Norway have made the mobile
phone number a user's primary phone number, and the user can be reached only on
this number. Traditionally, operators have offered their customers net-centric
logic for their call handling and switchboards and have used mobile phones as
their only phone. Because users use the same phone at work and
privately, they have only their mobile number, and the number follows
the user and not the company.

When my team started deploying Microsoft Office
Communications Server 2007 R2 for these companies, they wanted the
solution to be built by using mobile phone numbers as the primary number
when calling from Microsoft Office Communicator. As a result, operators
in Norway, such as Telenor and Netcom, are offering IP trunks
that integrate with Communications Server 2007 R2. By using these IP trunks,
they can rewrite the caller's number from a PSTN number to a mobile phone
number before the call reaches the PSTN network. This enables users to have a
single mobile number. And when the called party calls back to the mobile phone
number, the Communications Server PSTN number is called at the same time by using
dual forking that is provided by the operator. However, when Exchange Unified
Messaging (UM) is added to this scenario, issues arise. This article explains
the problem and gives the solution.

Author: Ståle Hansen

Publication date: January 2011

Product version: Microsoft
Office Communications Server 2007 R2, not verified for Microsoft Lync Server

The Problem

If you add
Exchange Unified Messaging (UM) to the mobile-phone-as-primary-number scenario
described earlier in this article, you get an issue. The integration itself
works fine and as expected. The problem occurs when the users log off their
computers and go to meetings, drive home, or are generally not logged on. What
happens is that when the user is not logged on to Communicator and someone
calls, Communications Server answers the call in under a second. The
user's call forwarding settings in Communicator are ignored, and the call
is forwarded to Exchange UM. As a result, the user loses the call on the
mobile phone. Exchange UM, therefore, breaks the solution. This is by design
and my team has not been able to implement Exchange UM in the unified communications
(UC) setting in these scenarios until now.

Using Exchange UM with Communications

If Exchange UM is
causing some issues why is our team so eager to implement Exchange UM in these
scenarios? When using the operator's net-centric voice mail features, some
technology and integration is lost. For example, by default, users get a Short
Messaging Service (SMS) message that tells them they have a new message, and
they can call in and hear the message. Some users configure their voice mail so
that it sends an e-mail with a .wav file of the message to their inbox. However,
after listening to the .wav file in Outlook, the message is still "unheard" if
the user calls the operator voice mail. There is no integration between the
operator's voice mail and Exchange. That is why we want to have Exchange UM
deployed to have a complete UC solution.

Exchange UM has several
advantages, such as the following:

  • Integration
    with the Exchange inbox: Messages that are heard or read in Microsoft Office Outlook
    or Microsoft OutlookWeb App, oron a mobile phone using Exchange ActiveSync
    are also read when the user calls the Exchange UM service.
  • Call
    back functionality directly for Outlook Web App: Users can have Exchange UM
    call them and play the message on the phone of their choice.
  • Note
    field integrated in Outlook and Outlook Web App: This allows users to take
    notes in Outlook while listening to the message, and then saves and indexes the
  • Call-in
    access to the calendar: Users can call Exchange UM and rearrange their
    calendar, which is very handy when late for a meeting driving a car.

Read more about
the Exchange UM server role.

The Solution

After about a
year of research, I found a way to work around this issue that Exchange UM has
with Communications Server by using Front End Server scripts and a program that
puts the call on hold for a given period of time. I came across a Scandinavian
developer company called Competella. They develop applications based on Unified
Communications Managed API (UCMA) and are currently developing
a switchboard attendant that integrates call control with an advanced
directory search tool to enable access to presence, calendar, e-mail, and IM.
The system adds attendant call control functionality to Communications Server
beyond the level found in legacy PBXs. They developed a script and a program
that checks the status of the user. If the user is offline, it will put the
call on hold for 20 seconds before forwarding the call to Exchange UM. This
solves the problem with users who use only a single mobile number. This also
works if a user has their status set to "in a mobile call" by third-party
programs that get free/busy information from the operators of a user's mobile


By using the
script and program from Competella we are able to complete our UC deployments
with Exchange UM when a user's mobile phone is their primary and only number.
With this we are able to implement enterprise voice mail for mobile phones as
well as in Communications Server.

Additional Information

To learn more, check out the following:

Keywords: Exchange 2010 UM,
OCS 2007 R2

Lync Server Resources

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Comments (1)
  1. Damien says:

    Unified Communications

    Integrate audio, video & web technology for unified communication based solutions

    Blackboard Environment Learning Preparations

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