Incorrect Modem Connection Speed Is Displayed (227695)


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 Q227695

SYMPTOMS

Modem connection speeds may be incorrectly displayed in Dial-Up Networking. Values that exceed the maximum speed of the modem may be displayed. Commonly reported values are 115,200 and 57,600.

CAUSE

There are two different values that can be reported when a modem connection is initiated:
  • The Data Terminal Equipment (DTE) speed
  • The Data Circuit-terminating Equipment or Data Communications Equipment (DCE) speed
The DTE speed is the speed between the computer's central processing unit (CPU) and the modem. The DCE speed is the actual connection speed. When you make a modem connection, the connect string that is returned from the modem is compared to values in the Modem.inf file that matches the modem. If there is no corresponding entry in the Modem.inf file, the DTE speed is displayed instead of the DCE speed.

RESOLUTION

A custom .inf file for the modem is required to resolve this issue. Check with the modem's manufacturer for an updated .inf file.

STATUS

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

MORE INFORMATION

You can also view the connection speed in the modem log file. To enable logging:
  1. Click Start, point to Settings, and then click Control Panel.
  2. Double-click Phone and Modem.
  3. Click the Modems tab.
  4. Click the appropriate modem.
  5. Click the Diagnostics tab.
  6. Click to select the Record a Log check box.
  7. Click OK.
  8. Initiate a dial-up connection.
A log file named Modemlog_modemname.txt is recorded in the %SystemRoot% folder (where modemname is the name of the modem). The following text is an excerpt from a sample log file:

04-28-1999 16:00:40.114 - Send: ATDT#,###-####<cr>
04-28-1999 16:00:56.267 - Recv: <cr><lf>CONNECT 28800<cr><lf>
04-28-1999 16:00:56.267 - Interpreted response: Connect
04-28-1999 16:00:56.267 - Connection established at 28800bps.

For additional information, please see the following article in the Microsoft Knowledge Base:

183807 Data Terminal Equipment and Data Circuit-Terminating Explained

Modification Type:MajorLast Reviewed:11/13/2003
Keywords:kbDialUp kbenv kbHardware kbprb KB227695
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