U.S. Robotics Courier I-Modem ISDN Modem Does Not Connect at Higher ISDN Speeds (238915)


The information in this article applies to:

  • Microsoft Windows 2000 Server
  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows 2000 Professional
This article was previously published under Q238915
IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SYMPTOMS

When you connect to an Internet service provider (ISP) with a U.S. Robotics Courier I-Modem, performance may be slow.

CAUSE

This behavior can occur if Windows 2000 has detected that the I-Modem has an older BIOS and has disabled the protocol options.

RESOLUTION

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To resolve this issue, use any of the following methods:
  • Update the modem's firmware. For an external modem, update to version 2.7.6 or later. For an internal modem, update to version 2.1.4 or later.
  • Add *v2=5 to the modem's initialization string. To do this:
    1. Start Registry Editor (Regedit.exe).
    2. Locate the following key

      HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4D36E96D-E325-11CE-BFC1-08002BE10318}\000x\Protocol\ISDN\V120_64K

      where 000x has a DriverDesc value of "Courier I-Modem ISDN-V.34 Internal."

    3. Modify the "1" value; change the string to include a 5, so that the string reads:

      AT*V2=5

    4. Click OK to save the value.
    5. Quit Registry Editor.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

MORE INFORMATION

The value for the AT*V2=x string can range from 0 to 5 for the Data B channel. These values have the following meanings:

0: Autodetect
1: V.120 rate adaptation only
2: V.110 rate adaptation only
3: Modem or fax only
4: Clear-channel synchronous
5: Asynchronous to synchronous PPP conversion

Modification Type:MajorLast Reviewed:11/13/2003
Keywords:kbenv kbHardware kbprb KB238915
©2003 Microsoft Corporation. All rights reserved.