Fax transmission may not finish after a connection is established in Windows Vista

When you try to use Windows Fax and Scan to send or receive a fax in Windows Vista, the transmission may not finish after a connection is established.

This issue may occur if one of the following conditions is true:

• There is line noise over the telephone line that is connected to the modem.
• You experience unexpected behavior from the modem.
• There is a timing issue between the computer and the modem.

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To work around this issue, you must use a different class support to retransmit the fax. To do this, follow these steps:

1. Click Start
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   , type device manager in the Start Search box, and then click Device Manager in the Programs list.
2. Expand Modems, right-click the modem that you use, and then click Properties.
3. On the Diagnostics tab, click Query Modem.
4. In the Command column, locate AT+FCLASS=?, and then note the value in the Response column.
   
   Note If the Response column contains a value of 1, 2, or 2.0, the modem supports Class 1, Class 2, and Class 2.0, respectively.
5. Click Start
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   , type regedit in the Start Search box, and then click regedit in the Program list.
6. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\Software\Microsoft\Fax\TAPIDevices
7. Expand TAPIDevices, and then click the device ID of the modem.
8. Click Modem, right-click FixModemClass, and then click Modify.
9. In the Value data box, type one of the following, depending on the class that you want to set:
   • Type 1 to set the fax modem to use Class 1
   • Type 2 to set the fax modem to use Class 2
   • Type 20 to set the fax modem to use Class 2.0
10. Exit Registry editor.
11. Restart the fax service. To do this, click Start
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    , type Services in the Start Search box, and then click Services in the Programs list.
    
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    If you are prompted for an administrator password or for a confirmation, type the password or click Continue.
12. In the Services list, click Fax, and then click Restart.
13. Try to send the fax. If the issue occurs again, repeat steps 1 through 12 and set the modem to use a different class.

For more information about sending a fax in Windows Vista, visit the following Microsoft Web site: