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Article ID: 812460 - Last Review: January 11, 2015 - Revision: 3.0

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You may experience poor sound quality in Microsoft Windows Messenger when you use this component over a virtual private network (VPN) connection.


This problem may occur if your VPN connection is configured to use a dial-up modem connection to the Internet.

In this situation, when you use Windows Messenger to make a call to another Windows Messenger client or to the Public Switched Telephone Network (PSTN), Windows Messenger does not use the most bandwidth-efficient audio codec. Windows Messenger uses SIREN when it connects to another Windows Messenger client, or it uses G.711 when it connects to the PSTN. Therefore, the sound quality over the VPN connection in this scenario is poor.


Service pack information

To resolve this problem, obtain the latest service pack for Microsoft Windows XP. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
322389  ( ) How to obtain the latest Windows XP service pack

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: (
Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language. The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date         Time   Version           Size     File name   Platform
   07-Jan-2003  19:49  5.1.2600.1155     845,312  Dxmrtp.dll   i386
   07-Jan-2003  19:50  5.1.2600.1155   1,048,064  Dxmrtp.dll   ia64
   03-Jan-2003  17:39  5.1.2600.1155     845,312  Wdxmrtp.dll  ia64	


Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Microsoft Windows XP Service Pack 2.

More information

For additional information about VPN connections in Windows XP, click the following article number to view the article in the Microsoft Knowledge Base:
314076   ( ) HOW TO: Configure a Connection to a Virtual Private Network (VPN) in Windows XP

Applies to
  • Microsoft Windows XP Professional
  • Microsoft Windows XP Home Edition
kbnosurvey kbarchive kbautohotfix kbHotfixServer kbwinxpsp2fix kbqfe kbwinxppresp2fix kbfix kbbug KB812460
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