Basic Fax Modem Software Troubleshooting

This document contains basic troubleshooting procedures for fax modem cards and software errors and difficulties. The information on Commworks specific problems is supplied to us by Traveling Software, Inc. For a more complete listing of Commworks documents available from the FaxBack^® service, you may order FaxBack^® catalogue 5 by calling 800-846-4526 from a touch-tone phone.

Possible causes:

• Another program or device driver has control of the fax modem.
• The COM (serial) port and IRQ (interrupt) values are set incorrectly in Windows.
• The fax modem initialization string needs to be modified to communicate with another modem and/or fax machine.
• The computer is not communicating with the fax modem.
• The fax printer driver is not set as the default Windows printer.
• The baud rate of the modem needs to be lowered to communicate correctly with another fax machine or modem.
• Call waiting is interrupting the fax modem’s transmissions.
• Newly added software is conflicting with the communications program.
• The communications program is corrupt and needs to be reinstalled.

Basic Troubleshooting

Another software program has control of the fax modem

Make sure that no other DOS or Windows communication program has control of the fax modem. Exit all programs except the communication program and try accessing the fax modem again. If you are using a Windows based communication application, exit Windows completely and when you re-Enter, try the communications program again.

COM port and IRQ values in Windows

If the communication program is run through Windows, make sure that Windows ports are set correctly. The following example demonstrates how to set up COM1 in Windows.

1. In the Program Manager, double-click on the Main program group icon.
2. In the Main program group, double-click on the Control Panel icon.
3. In the Control Panel, double-click on the Ports icon.
4. Click on COM1, then click on the Setting button. In the Settings for COM1: window, click on the Advanced button.
5. Click on the down arrow beside the Base I/O Port Address: setting. Use the mouse to click once on 03F8 to select it.
6. Click on the down arrow beside the Interrupt Request Line (IRQ): setting. Use the mouse to click on the number 4 to select it.
7. Click on the OK. The System Setting Change window appears. Click on the Restart Now button for the changes to take effect.

You can follow the same procedure for checking the COM port and IRQ values in Windows. The following chart contains the default values.

COM Port	Address	IRQ
COM1	03F8	4
COM2	02F8	3
COM3	03E8	2,4,5
COM4	02E8	2,3,5

Fax modem’s baud rate

The baud rate of a modem is the speed at which it communicates information. If you are receiving error messages referring to communication problems, lower the baud rate of the modem software. Consult the communications software documentation for specific information on changing the fax modem’s baud rate.

Call Waiting

Call waiting can interrupt the fax modem’s ability to communicate because of fluctuations in the signal from the telephone line when another call is coming into the line. To disable call waiting when you are using the fax modem, the initialization string needs modification. Consult the communications software documentation for information on changing the fax modem’s initialization string. Add *70 to the phone number and try using the communications software again (*70 is a function in the phone system itself that turns off the call waiting--not just when you are using a modem).

Fax printer driver

When you send a fax, the software usually accesses the fax modem via the printer driver. If you are using a Windows based communications program, make sure that the faxing software is set as the default printer. To do this:

1. In the Program Manager, double-click on the Main program group icon.
2. Double-click on the Control Panel icon in the Main program group.
3. Double-click on the Printers icon in the Control Panel.
4. If the faxing software driver is not in the Default Printer box, click on the fax printer driver in the Installed Printers box.
5. Once the fax printer driver is highlighted, click on the Set As Default Printer button to select it.
6. Click on the Close button in the upper right hand corner of the Printer box.
7. Try using the fax communications program again.

Newly added software

Some software programs may interfere with the fax modem’s ability to communicate. If you have added any new software to the system, including any desktop programs that replace the Program Manager, remove all references of the new software. If this is not possible, reinstall the fax modem communications program.

Fax modem communications program corruption

Corruption in the communications software program may be causing problems when you try to access the fax modem.

1. To see if there is corruption on the hard drive, at the C:\> prompt outside of Windows type:
   scandisk c: /autofix /nosave
   and press Enter. Scandisk scans the file structure of the hard drive, identifies and repairs many errors that the program locates.
2. he last screen reports any problems or repairs that it made to the hard drive. Use the Tab key on the keyboard to highlight the word Exit and press Enter to return to the C:\> prompt.
3. Refer to the communications software manual and reinstall the software program to make sure that there is no corruption. After you finish installing the software, try accessing the fax modem again.

Fax modem communicating with the computer

If the fax modem is not communicating with the computer, the communications software will not work.

1. To determine if the fax modem is able to communicate with the computer, exit Windows completely and reboot the computer.
2. As soon as you see "Starting MS-DOS" appear on the screen, press the F5 key on the keyboard to boot the computer clean and take you to a C:\> prompt. At the C:\> prompt in DOS, type:
   echo atdt >com1
   and press Enter. You should now hear a dial tone if the fax modem is on COM1. If the fax modem is located on a different COM port, substitute COM2, COM3 or COM4 for COM1 in the above command.
3. Once you hear the dial tone, reboot the computer and attempt to use the communications program again.

If you do not hear the dial tone, the fax modem is not communicating with the computer or the telephone. For further troubleshooting procedures for the fax modem hardware, see document 1948.

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