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Modem best practices

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Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Best practices

The following list provides best practices for installing and using modems. Review this list before you use modems.

  • Turn on any external modems before you start Windows.

    If an external Plug and Play modem is not turned on before you start Windows, Windows may not detect it correctly.

    For more information, see Troubleshooting modems.

  • If Windows does not support your modem make and model, check the manufacturer's Web site for the latest installation or .inf file.

    The installation files, particularly for new modems, are often added or updated by manufacturers. If you cannot find your modem listed in Windows, look in the manufacturer's documentation to find if the modem has the same characteristics as another supported modem.

    Some legacy modems are not supported. For a list of supported modems, see Support resources.

    For more information, see Installing a modem.

  • Use the Phone and Modem Options diagnostics utility to test and troubleshoot a modem.

    To see if the modem is responding to commands, in Control Panel, double-click Phone and Modem Options. In Phone and Modem Options click the Modems tab, right-click the modem that you are interested in, click Properties, and then click the Diagnostics tab. You can also configure logging and view logs at this location.

    For more information, see Modem diagnostics, Test a modem, Log and view modem commands.

  • Before you connect to another computer or online service provider, check the hardware settings for your modem.

    The data connection parameters for two modems need to be identical for them to connect successfully. Refer to the documentation provided by your service provider for the correct settings. Typical settings are:

    • 8 data bits

    • None for parity

    • One stop bit

    Bulletin boards and most service providers use these settings. If these do not work, try seven data bits, even parity, and one stop bit. A few online service providers use these settings. Other settings are extremely rare.

    For more information, see Hardware settings.

  • When you install the same make and model of modem on multiple ports, first install it on one port, and then duplicate the installation for the remaining ports.

    For more information, see Duplicate a modem installation on multiple ports.

  • To change the same setting for modems installed on multiple ports, first change the setting on one modem and then copy the change to the remaining modems.

    For more information, see Copy modem properties to modems on multiple ports.

  • Rarely, you may have to configure the COM port before installing a modem.

    The COM port is automatically configured for most modems. The following exceptions may occur:

    • If you install an internal modem card that is not compatible with Plug and Play specifications, you may have to configure its built-in COM port by using Add Hardware in Control Panel before you can install the modem.

    • If you are using PCMCIA drivers, your computer will detect and configure the PCMCIA modem cards automatically when you first insert them. If the card is not detected, you might need to run Add Hardware in Control Panel to configure the card's built-in COM port. You then install the PCMCIA modem by using the Phone and Modem Options in Control Panel.

    For more information, see Install a modem, Troubleshooting network and dial-up connections.

  • If you create a direct connection to a computer, Windows CE device, or other device, make sure that the maximum port speed in the connection properties is set as high as supported by the device.

    The initial maximum port speed for a direct connection created in the Phone and Modem Options in Control Panel is 19.2 Kbps. If the device on a connection supports higher data transmission speeds, you can increase the maximum port speed to that supported by the device. To find the correct speed, refer to the manufacturer's documentation provided with the device.

    For more information, see Change the maximum modem port speed, Optimizing data transfer speed.