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If this article does not describe your hardware-related issue, please see the following Microsoft Web site to view more articles about hardware:


When you attempt to dial out with a modem, you may receive any of the following error messages:

  • Error 630: The computer is not receiving a response from the modem. Check that the modem is plugged in, and if necessary, turn the modem off, and then turn it back on.

    Communication port is invalid or busy.

    Error 630:

    The modem is not responding correctly. Please verify that the modem is plugged in to the computer and to the telephone line. If the problem persists, please select 'Help' button to start the Windows Modem Troubleshooter.


This behavior can occur if you have the "Support SerialKey devices" Accessibility option configured to use the COM port to which your modem is connected.


To resolve this issue:

  1. Click Start, point to Settings, click Control Panel, and then double-click Accessibility Options.

  2. On the General tab, either:

    • Click to clear the Support SerialKey devices check box, or

    • Click Settings, click a different COM port in the Serial port box, and then click OK.

  3. Click OK.

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