Can Lync send audio/media direct to the PSTN using G.711?

Well sort of!

G.711 is a voice codec, used by the majority of IP PBXs to encode their audio.

OCS and Lync can use it in some circumstances, although Microsoft also has their own codec called RTAudio, which is an adaptive codec and thus aims to cope well with challenging network bandwidth.

In OCS there is the Mediation role which was used to convert from RTAudio to G.711 as media flows out to the PSTN.

In Lync the mediation role has been allowed to be collocated with the Front End server. This is possible because of something called Media Bypass, which allows calls to the telephone system (PSTN) to send the signalling through the Front End with collocated Mediation server, but not the media. So instead of the end Lync client talking RTAudio to the Mediation server and then having it converted to G.711 and sent out to the PSTN Gateway, the media goes direct to the gateway. This allows for less load on the Mediation server.

There are various caveats, such as what happens if the client is external. In this case the media will come in as RTAudio via the edge server and need translating via the Mediation server. Depending on the level of externally originated PSTN traffic, you may consider a separate Mediation server pool for load purposes.

Equally another point is that for large FE pools where SIP Trunking is used (Rather than E1 connections from gateways) it is suggested to have a Mediation server pool so as to simplify the relationship between the provider of PSTN connectivity and the pool. (Simply put to allow for perhaps 2 mediation servers each with individual trunks for HA, rather than a pool of 8 combined FE and Mediation boxes with all the required trunks!)

So to answer the question, yes in some ways, and with the right provider a Lync client could potentially send audio (media) traffic direct to the PSTN, however signalling still needs to go through the Front End/Mediation server. Therefore the only scenario where media would flow without the FE is where a call has already been setup. At that point if the FE went down, the call would still be able to continue.


Connecting Lync 2010 or OCS 2007 R2 to the PSTN


Having just written a long (ish) post on a forum, I thought I would post it here for future reference.

These are high level methods of connecting OCS 2007 R2 or Lync 2010 to the PSTN.

There are three options;

In terms of capability of connection to the PSTN (Telephone network) functionally nothing much has changed in Lync 2010 compared to OCS 2007 R2 other than the need for SRTP support in gateways.

The lack of change is not a bad thing, as you really already have plenty of options!!



Traditionally people have ISDN connections to the telephone network which in the USA are called T1 lines which give you a potential 24 channels (calls). Lync 2010 Server has no way of connecting to these ISDN lines without some form of interface. This could be putting an ISDN interface card into your server, but in general is by using a gateway device from the likes of Audiocodes or NET Quintum.

The gateway terminates the ISDN lines and then translates the audio into RTP streams (SRTP for Lync) and SIP for signalling (i.e. setting up who is calling who).

Generally this is the most used option as by terminating the ISDN lines on the gateway it is then possible to route calls either to Lync or to an existing PBX system



The next most common option is to use an existing PBX to terminate the ISDN lines and have it talk to Lync, either through a gateway (kind of a reverse of the order above) or, the PBX might be able to talk SIP, and use TCP to talk over Ethernet to Lync.



Instead of dealing with traditional ISDN lines the Lync server will connect over IP (TCP or UDP) Port 5060, to an ITSP (Internet Telephony Service Provider). For example people like Verizon, BT, Global Crossing etc.

This allows OCS to route and receive calls directly to the PSTN without the need for any legacy telephony equipment.

Sometimes, even with the above solution, a gateway can be useful, which can be used more like a session border controller, giving options to manipulate the traffic as it passes from Lync to the ITSP.


Hope that clears things up.


Digicert being most impressive!


I’ve blogged about Digicert before, but over the last few days I’ve had yet another change to use them and been seriously impressed!

I was setting up an OCS 2007 R2 lab and got to the section where I needed to setup Forefront TMG to proxy connections to the OCS Web Components on my Standard Edition front end.

I created the cert request using the certificate wizard in the OCS administrative tools as it is the easiest way I know to mark the private key as exportable.

Having done that I submitted the request to Digicert and, because it was a domain I have already validated, the certificate was issued within five minutes.

I installed the certificate on the Front End, exported it, and installed it on the Forefront TMG box.

Then for testing I accessed the relevant website externally. Things looked like they worked but on one device I got a trust error. It was late, and I didn’t have time to investigate so I left it.

The next day I received an email from Digicert as below:

We just ran an installation check on the DigiCert SSL certificate that you installed on and it appears that the server needs to be configured for maximum compatibility. You will need to install the Intermediate certificates to the server in order to ensure compatibility with legacy browsers and mobile devices.

On Windows platforms, the easiest way to do this is to use our certificate utility. Just visit and download the Certificate Management Tool. After running it on the server, click the Repair button. Some servers require restarting the services or restarting the whole server after making this change.

You can verify that the problem is fixed at

If you have any problems correcting this issue, please contact our helpful support team and we will be happy to help.

Now I knew about the utility and have blogged about it before, but to be told this is the problem proactively was brilliant!

I ran the utility, it installed the intermediate CAs properly and all is well!

Thanks Digicert

Note: As an Exchange MVP, DigiCert has provided me certificates to use in test labs, without which I may not have had the opportunity to try their service.

Hosted Pilot for Microsoft Unified Communications – Features

As promised here is a post looking in a little more depth at the features of the Hosted UC Pilot from Microsoft.

Firstly I will look at some of my favourite features and then will take a look at what is not available.

The first thing that strikes you as you log into Outlook Web App, is that you now have a fully fledged Exchange 2010 mailbox.

This is accessed using the URL.

One of the nicest things here is that you can start sending IMs immediately by using the integrated IM functionality. Obviously this is not as feature rich as Office Communicator or even Communicator Web Access but it gets you started. Another new addition is the ability to see presence within OWA as can be seen in the email and top right of the screenshot below:


In my previous post on this subject I showed the process of logging into Office Communicator. Having done so I started poking around, and the first thing I tried was adding a federated user.

This gave me the following error:


The link for more info pointed here:

I then tried to add a friend at Microsoft – Brett Johnson

Surprisingly this worked as can be seen below, the globe icon shows up next to Brett which means that Federation is working for users at Microsoft but not external domains.


I then tried a bunch of other UC functionality such as desktop sharing, and peer to peer voice calls. Everything worked well! Sadly, one thing that is not available is Enterprise Voice which means that you can’t go making phone calls on the system.

One major thing that is really important to understand is that this is a multi tenant system on which you can see all the other accounts that people have created! There is NO segregation at all!!

So all in all this is a great service for anyone wanting to test out the full range of Microsoft UC functionality minus of course Enterprise Voice.



Opening the OCS Help File gives HTML blocked content error

I’ve been doing a bunch of work recently with OCS in various lab scenarios and am really pleased that the OCS product group have bundled all their documentation into a CHM file like the Exchange team have done for a while.

The only weird thing about using the downloaded help file (see link below) 

is that on opening it, it doesn’t show content instead giving an error message as shown below:


So what it turns out, is that this only happens when you download the CHM file directly because when doing that, you are prompted about the possible security threat from opening it.

To get around this, I uncheck the box to always prompt on opening this type of file;


at which point, the CHM file works correctly.


Hope that helps someone.



Hosted Pilot for Microsoft Unified Communications – Setup


As promised here is more info about the new hosted pilot for UC from Microsoft.

On clicking the register link, some basic info is required, but all relatively simple stuff, like number of PCs, company name and phone number.

Having filled the form your account is created and then you are prompted to add other users. At this point I created one for my wife too!

Next you are redirected to the resources page –

The relevant section is towards the bottom of the page and gives a link to a Silverlight based app which shows various mini videos outlining key features and functionality.


This information is actually pretty good! It is a reasonably clear and easy guide to the key elements of Unified Communications according to Microsoft!

So having got this far, the next step is to get the Microsoft Office Communicator client installed on a few machines, for this purpose the confirmation/information mail points you to the evaluation version of MOC here –

Once MOC is installed update it with the latest MOC patch as shown in my blog post here:

Once MOC is fully installed and patched fire it up from the Start menu and login using the credentials provided:

One thing to note is that when I first opened MOC it was set to the default log in name and wouldn’t let me change it! So to do so I clicked the drop down menu in the top left of the sign in window next to the MOC icon and selected Connect / Change Sign-in Address

I then entered the correct address as shown:


At this point, clicking OK takes you back to the sign in window:


Now that the sign-in address is correct click Sign In

Enter the details as instructed using the sip/email address for the username and then click Sign In again.


At this point you will be signed in and can start using OCS!

Have fun!!

In a while I will post again detailing some of the features which are, and more importantly are not available in the online pilot.

Updating Microsoft Office Communicator – April 2010 patch

Recently there have been a bunch of new updates for Office Communications Server 2007 R2 and it’s accompanying client Microsoft Office Communicator 2007 R2.

I will post later with screenshots of the server updates but for now here is the location and process to update MOC.

First download the patch from the link below:

You will notice that much more information is available from the following location –

For example from the above KB article we can see that there are many bug fixes included.

To install the update once simply double click the .msp file that you have downloaded and follow the steps below:

Click Next


Accept the license terms and click Next


If prompted accept (Click Yes) to the UAC request

Click Finish


All in all it’s really that simple!

Microsoft Unified Communications information rollup – April 2010

As with my old blog I will continue to post these monthly updates from Microsoft and will highlight anything that I’ve had particular experience with…


Antigen & Forefront

Forefront Team Blog

Forefront Server Security Support Blog


You Had Me At EHLO…

Microsoft UK UC Blog

Office Communication Server & LiveMeeting

Office Communications Server Team Blog

Office Communicator Team Blog


Microsoft Outlook 2010


Next Hop Technical Resources – Office Communications Server | TechNet

The Master Blog


Antigen & Forefront

Microsoft Forefront Server Security Management Console Documentation

Forefront Server Security Management Console allows administrators to easily manage Forefront Security for Exchange Server, Forefront Security for SharePoint, and Microsoft Antigen.


Microsoft Exchange Server 2007 SP2 Help

This download contains a standalone version of Microsoft Exchange Server 2007 SP2 Help.

Hosted Messaging Collaboration

Office Communication Server & LiveMeeting

Microsoft Office SharePoint Online

Microsoft® Office SharePoint® Online is a collection of Web-based tools and technologies built on Microsoft Office SharePoint Server 2007 that help you store, share, and manage digital information within your company. This white paper describes the services and features that are included with the Standard offering of SharePoint Online.

Microsoft Exchange Online Standard

Microsoft® Exchange Online is a hosted enterprise messaging solution based on Microsoft Exchange Server 2007. Exchange Online services include advanced e-mail features as well as calendaring, contact, and task management capabilities. This white paper describes the services and features that are included with the Standard offering of Exchange Online.




Antigen & Forefront


Microsoft Exchange Server Profile Analyzer

Collect estimated statistical information from a single mailbox store or across an Exchange Server organization.

Microsoft Exchange Server Profile Analyzer (64 bit)

Collect estimated statistical information from a single mailbox store or across an Exchange Server organization.

Exchange 2010 Language Pack Bundle

This download contains the most recently updated language packs for Exchange 2010. The language bundle includes all packs for all supported languages.

Exchange 2010 Language Pack Bundle, March 2010

This download contains the most recently updated language packs for Exchange 2010. The language bundle includes all packs for all supported languages.

Office Communication Server & LiveMeeting



What’s New with Exchange 2010!

Friday, April 09, 2010 9:00 AM Central Time (US & Canada)

Got Exchange Questions? We’ve Got Answers.

Now, more than ever, your customers require cost-effective and flexible communication tools. Learn how Microsoft Exchange Server 2010 can help your customers achieve new levels of reliability and performance with features that simplify administration and  protect communications. As the cornerstone of Microsoft’s Unified Communications solution, Exchange Server is a flexible and reliable messaging platform that can help lower messaging costs by over 50% and  increase productivity with anywhere access.

Hosted by: Brendan Newell – Senior Metro Partner Technology Advisor


9:00 – 9:30am CST What’s New with Exchange 2010

9:30 – 10:00am CST Open Discussion, Q & A

(10-11am EST)

Upcoming Exchange Server 2010 Discussions with Brendan

Tips & Tricks to Migrate to Exchange 2010

Leveraging Exchange 2010 for Unified Messaging

High Availability – Disaster Recovery

Hosted Exchange

Exchange 2010 – How best to secure your infrastructure


Momentum Webcast: Ask Rieva Live!: Collaboration in a Mobile Environment (Level 100)

Thursday, April 22, 2010 10:00 AM Pacific Time (US & Canada)

Welcome to Ask Rieva Live! – a live chat digital event series brought to you by the Microsoft Business Resource Center.  Join business expert Rieva Lesonsky, founder and President of GrowBiz Media and former editor of Entrepreneur Magazine, to delve into key topics on managing and growing your business, with a live Q&A session. 

In this session: As the economy heads towards recovery companies are seeking ways to invest in and grow their businesses, while keeping their overhead low. The best way to do this is look at your expenses—and cut costs wherever possible. Got cost-cutting questions? Rieva has answers!

Presenter: Rieva Lesonsky, Founder and President, GrowBiz Media

Rieva Lesonsky is the founder and president of GrowBiz Media, a content and consulting company that helps entrepreneurs start and grow their businesses, and former editor of Entrepreneur Magazine. Follow Rieva on Twitter @Rieva. Visit to read more of Rieva’s insights on small business and to buy her newest book, Marketing 101: Quick Tips for Marketing Your Business.

View other sessions from Momentum: Drive Your Midsize Business Forward

If you have questions or feedback, contact us.


Microsoft Office System Webcast: Tips and Tricks for Outlook 2007 and Office 2010 (Level 100)

Wednesday, April 14, 2010 11:00 AM Pacific Time (US & Canada)

We invite you to attend a Live Meeting presentation that will help you get the most out of Outlook 2007. Learn about new features and timesavers to help you in your day-to-day work. This session is good for beginner and intermediate users. We’ll also include a look at some of the new features in Office 2010.The time you take to attend this session can help save you time later – past participants report saving from 15 to over 30 minutes a day after attending a Tips and Tricks session. Led by an expert Microsoft technology presenter, the session will be informative and entertaining, designed to help you learn how to work more effectively. 

Presenter: Jed Warren, IT Training Specialist, New Horizons Learning Center

Jed Warren has over 10 years experience in IT. He has spent the last three years doing hands-on computer training for New Horizons Computer Learning and Microsoft. Recognized as the number one applications instructor worldwide for 2006 at New Horizons, he continued training thousands of end users in beginning, intermediate and advanced classes for over 27 different courses. As a current MCP and MCT, Jed also holds certifications in IC3, ITIL, Comptia A+, Net +, and Security +, Desktop Support Technician, and a master certification in Microsoft Office Systems.

View other sessions from Microsoft Office System Webcasts: Enhance Your Skill Set with Expert Tips

If you have questions or feedback, contact us.

New KB’s

Antigen & Forefront

Antigen for Exchange SP2: Description of Hotfix Rollup 1 for Antigen 9.0 Service Pack 2 (Updated)

Forefront Sec Exchange Svr EN: Some default deletion messages in Forefront Security for Exchange Server may mislead a user or an administrator to assume that an error occurred or that a virus was found (Updated)


Exchange Svr 2003 SP2 EN: A new feature known as Intelligent Message Filter in Exchange Server 2003 prevents regular messages from being moved to the Junk E-mail folder

Exchange Svr 2003 SP2 EN: "Outlook cannot display this view. Unknown Error" error message is generated in Outlook client and Event ID 9667 is logged on an Exchange Server 2003 server

Exchange Svr 2003 SP2 EN: An error occurs when an Exchange server 2003 user tries to open more than one delegate mailboxes of Exchange Server 2010 in Outlook 2003

Exchange Svr 2007 SP2 AL: A Computer that is running the Microsoft Exchange Server 2007 Client Access Server  role becomes slow when a user tries to open a folder that contains many items (Updated)

Exchange Svr 2007 SP2 AL: "451 4.4.0 DNS Query Failed" status message in an Exchange Server 2007 Edge Transport server

Exchange Svr 2007 SP2 AL: Later updates do not match a calendar item that an Exchange Server 2007 user updates by using Exchange ActiveSync on a mobile device

Exchange Svr 2007 SP2 AL: You receive an "0x800423f0" error message when you perform system state backups on the passive node of Windows Server 2008-based Exchange Server 2007 CCR clusters

Exchange Svr 2007 SP2 AL: An external recipient misses the last occurrence of a recurring meeting request or a recurring appointment that is sent from an Exchange Server 2007 user

Exchange Svr 2007 SP2 AL: The subject of a confirmation message is garbled for certain languages when a remote device wipe operation is performed in Exchange Server 2007

Exchange Svr 2007 SP2 AL: The sender address of a forwarded meeting request does not include “on behalf of” as expected in an Exchange Server 2003 organization and an Exchange Server 2007 organization mixed environment

Exchange Svr 2007 SP2 AL: A SSL certificate validation error is generated on an Exchange Server 2007 server when you run any test commands after you run the Test-SystemHealth command

Exchange Svr 2007 SP2 AL: A mailbox that was moved from an Exchange Server 2007 server to an Exchange Server 2010 server cannot be accessed by using Outlook

Exchange Svr 2007 SP2 AL: The Exchange Information Store service stops responding on an Exchange Server 2007 server

Exchange Svr 2007 SP2 AL: The Exchange Information Store service crashes on a Microsoft Exchange Server 2007 server when a user tries to access a specific calendar item

Exchange Svr 2007 SP2 AL: Read items are marked incorrectly as unread items in an Exchange Server 2007 public folder

Exchange Svr 2007 SP2 AL: You receive an error message when you use ExBPA to schedule a scan on an Exchange Server 2007 SP2 server

Exchange Svr Ent 2000 EN: You cannot connect to a mailbox store by using ExMerge after you restore the mailbox store to a recovery server in Exchange Server 2000 or Exchange Server 2003 (Updated)

Exchange Svr Ent 2003 EN: "Access Denied" Error Message When You Try to Use Outlook Web Access (Updated)

Exchange Svr Ent 2007 AL: Build numbers and release dates for Exchange Server (Updated)

Exchange Svr Enterprise 2010 AL: Description of Update Rollup 1 for Exchange Server 2010 (Updated)

Exchange Svr Enterprise 2010 AL: Certain third-party IMAP4 clients cannot connect to Exchange Server 2003 mailboxes through an Exchange Server 2010 CAS server

Exchange Svr Enterprise 2010 AL: You receive an error when you try to create a Unified Messaging Auto Attendant in the Exchange Management Console: "The pilotidentifier ‘string value’ is not a valid extension"

Exchange Svr Enterprise 2010 AL: The POP3 service crashes when a user connects to a mailbox through the POP3 protocol and the user is migrated from an Exchange Server 2003 server to an Exchange Server 2010 server

Exchange Svr Enterprise 2010 AL: Exchange Server 2010 Push Notifications does not work

Exchange Svr Enterprise 2010 AL: Description of Update Rollup 2 for Exchange Server 2010: February 18, 2010

Exchange Svr Enterprise 2010 AL: Error message when you import a third-party certificate into Exchange Server 2010: "The certificate status could not be determined because the revocation check failed"

Exchange Svr Enterprise 2010 AL: You cannot connect to an Exchange Server 2010 mailbox from Outlook Web Access

Exchange Svr Enterprise 2010 AL: This fix introduces the supports for Exchange Server 2010 page patching when a "-1022" disk I/O error is generated

Exchange Svr Enterprise 2010 AL: Event ID 2156 is logged on a computer that is running Exchange Server 2010

Exchange Svr Enterprise 2010 AL: On Exchange Server 2007 or on Exchange Server 2010, e-mail messages seem to disappear when you try to move them to a mailbox folder

Exchange Svr Enterprise 2010 AL: You receive error 1603 when you try to install the Exchange Server 2010 RU1

Exchange Svr Enterprise 2010 AL: You must enter your logon credentials two times when you log on to Outlook Web App

Exchange Svr Std 2003 EN: An e-mail message is corrupted after the Disclaimer rule is enabled on an Exchange Server 2007-based server (Updated)

Office Communication Server & LiveMeeting

Office Comm Svr Ent 2007 EN: Error message when you log on to Communicator: "Cannot Synchronize Address Book" (Updated)

Office Comm Svr Ent 2007 EN: You experience audio quality issues when many performance counters are logged on to Office Communications Server 2007 R2, Audio/Video Conferencing Server

Office Comm Svr Ent 2007 R2 AL: You cannot download the corporate address book, and you receive an error message when you use Communicator to log on Communications Server: "Cannot Synchronize Address Book" (Updated)

Office Comm Svr Std 2007 R2 AL: When you make an audio call to a Communicator Web Access user, you do not hear a ring tone until the other user answers the call

Office Live Meeting 2007 AL: Incompatibility between the Live Meeting 2007 console and the Intel PROSet/Wireless Wi-Fi software


Outlook 2003 Win32 AL: Description of the Office Outlook 2003 Junk E-mail Filter update: March 9, 2010

Outlook 2003 Win32 AL: The read receipt is not returned to a delegate in Office Outlook 2003

Outlook 2003 Win32 AL: Description of the Outlook 2003 hotfix package (Outlook.msp): February 25, 2010

Outlook 2007 Win32 ML: A shared folder is unexpectedly cached to the Offline Folder file in Outlook 2007 (Updated)

Outlook 2007 Win32 ML: Description of the Office Outlook 2007 hotfix package (Outlook-x-none.msp): January 27, 2010

Outlook 2007 Win32 ML: When you try to send an encrypted e-mail message in Office Outlook 2007, you are prompted for your smart card

Outlook 2007 Win32 ML: Description of the Office Outlook 2007 Junk E-mail Filter update: March 9, 2010

Outlook 2007 Win32 ML: "Microsoft Office Outlook had problems encrypting this message" error message when you send an encrypted e-mail message in Office Outlook 2007

OCS 2007 R2 now supported on Server 2008 R2

Just a quick post tonight as it’s been kind of busy today!

Ever since Server 2008 R2 came out people have been making the mistake of installing OCS on it! Annoyingly the install worked and then so did some of OCS but clearly not all!

So now, right on schedule Microsoft has released documents detailing how to get things working and providing support for installing OCS both on Server 2008 R2 and also in Server 2008 R2 based Active Directory environments.

The main document is linked below:

The key thing to be aware of is that Group Chat will still not work and that we are awaiting a patch in mid-April for that.

The next article details the issues faced when dealing with Server 2008 R2 and in particular, what to do when installing Server 2008 R2 AD schema and preparation updates into an existing forest with OCS already installed.



Re-launch of Microsoft Messaging and Mobility User Group (MMMUG)





Installing Exchange Server 2010 in Typical Configuration
“This article will discuss the decisions to be taken when installing Exchange Server 2010 in a single server environment and will show in detail the steps taken to do so….”

– Nathan Winters

OAB Repair Article
“As an Exchange Admin you have probably come accross the newer versions of Outlook that have the ‘cached mode’ feature. This is a relatively new feature that shipped with Outlook 2003 and Outlook 2007.”
– Simon Phillips

Exchange DB Corruption blog
“Just a high level overview of a procedure I used a couple of weeks ago to overcome database corruption at a business that had a single server and didn’t want a huge amount of downtime…..”

– Tony Brown


This post is essentially a re-issue of  he first of many MMMUG newsletters of the year. For those of you who have been regular MMMUG meeting attendees or to be honest for anyone who has looked at the site recently, you will have noticed that things were rather slow! Well, over Christmas I was very glad to be contacted by Tony Brown who offered to help out with the group. In particular he has done sterling work on putting together the new website which we are launching today!

Tony has worked really hard on the new site which has moved away from the Community Server platform to give us a solid base to build on. The site is live now and over the next few months we will be gradually adding functionality. For example, in the future, registration for the events will all be automatic via the website, there’s a calendar which will include lots of information about Exchange related news/releases and forum spam should be reduced.

If you’d like to see something implemented on the website then please let us know in the forum.

To sign into the new site, your old userid should be fine, but you will need to reset your password.

If you can’t login for any reason then please send an email to and we’ll get it sorted out.

We have the first meeting of the year penciled in for early May but we’ll send you more information when it’s confirmed – as long as you don’t unsubscribe of course. 🙂

Thanks for sticking with the group this far and here’s to a much more active future!

Nathan Winters Founder
Tony Brown Leader

Note – You can also find MMMUG on these social networks




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