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Using WinFax PRO with your DSL Modem (Sending Internet Faxes)

 US ROBOTICS 56K PCI Faxmodem is not a DSL ModemADSL Modem Westell 6100

Shown above is a typical internal PC fax modem and a DSL modem

At one time, fax/modems were a common hardware item that were bundled with many PCs.  In an effort for computer manufacturers to reduce prices, and because of the decline of dial-up Internet modem usage, fax/modems are not usually bundled with a computer and must be purchased separately as an add-on. While dial-up internet still being used, it’s rapidly being replaced by high speed internet service, such as DSL.  The DSL modem that is usually supplied to you when you subscribe uses the high frequency (25 kHz – 1 MHz) of your telephone line for internet service.  The lower frequency (4 kHz and below) is used for use for regular telephone calls (voice), fax and data calls.

So the question is, if I have a modem for my DSL connection, I should still be able to send a fax with WinFax, right?

The answer is no, with an exception.

During the 1980’s, modem manufacturers started adding the ability to fax with their dial up modems. You could send faxes directly from your computer with fax software that could communicate directly with the fax modem.  Soon after, they added the ability to receive faxes. By the mid to late 1990’s, most PCs came bundled with a fax/modem which could both send and receive faxes at speeds up to 14,400 bps. During this time, all the modem manufacturers came up with a few standards, we can call it a “language”, for faxing via the PC.  These standards still exist today, and are available in different variations.  Class 1, Class 2, and Class 2.0.  If you have a modem that supports Class 1, Class 2 or Class 2.0 then it is a fax/modem. Some fax modem models will support only one class (usually Class 1) , or multiple classes (such as Class 1 and Class 2.0).

To use WinFax PRO, you need a modem that has the ability to understand at least one of the fax classes.  DSL Modems are specifically designed to use the high frequency of the telephone line (25 kHz and up) and they are not designed to communicate to the computer using any of the fax classes. This is why you cannot send a fax via DSL using fax software on your PC.   A DSL Modem that supports a fax class does not exist.

I’ve sent faxes before using my DSL Modem, how was this possible if you say DSL modems don’t support fax?

When you send or receive an “internet” fax (using a service like eFax), it’s not actually being sent or received by your DSL modem. When you send a fax through the internet , your fax is routed to someone else (it’s uploaded to a internet fax service) which then handle the actual faxing.  In simple terms, its like you going to a nearby Kinko’s/Staples/Copy place, handing them the pages you want faxed, and paying them to feed the pages into a fax machine and dial the fax number for you. Of course the Internet Fax service does this process in the background and its completely automated, so it may appear your DSL modem is sending a fax but its only providing the means of getting your document to the Internet fax service.

Is there an Internet fax service for WinFax PRO?

Yes, this is the exception where you can use your DSL Modem to send internet faxes with WinFax PRO 10 (actually, all you need is a high-speed internet connection and WinFax PRO 10). A company called Concord Fax offers a plug-in for WinFax that adds Internet Fax service for WinFax PRO. If your interested in pricing or other details, contact Concord Fax. They are no longer actively promoting this service anymore, but I believe it still active for current WinFax users.


So, you have a few choices with WinFax PRO faxing.

Either you purchase a fax/modem that has Class 1, Class 2 or Class 2.0 capability (I’ll post information about choosing a fax modem in a future blog entry), or, use the Concord Fax plug-in to send faxes using WinFax PRO.

Using WinFax PRO with a fax/modem provides you the ability to have full control of the faxes you send or receive, you eliminate the costs of a  monthly fax service and you can benefit from a flat rate or long distance savings plan from your telephone company. It also provides an added security that only you and recipient will see the fax you are sending/receiving.

If you do add a fax/modem to your PC (internal, or external), ensure you add the appropriate DSL filter to it. These devices filter out everything above 4 kHz frequency since you do not want the 25 kHz-1 MHz frequency being heard by the fax modem. This would cause faxes to fail. A filter should be installed on every telephone, fax/modem, telephone answering device, or any other telephone device that uses the low frequency band (4 kHz and below). Some installations of DSL may not require the use of filters (Dry-loop DSL/Naked DSL). Check with your Internet provider if filters are required, if so, they can provide them for you.

If you decide you don’t want to install a fax/modem to use WinFax PRO, the only way to send a fax is subscribing to a third-party fax service.  Discard WinFax and use the Web interface the fax service provides, or the software they provide you. There are dozens of services available, some are better than others and some also provide toll-free numbers for you to receive incoming faxes.  Some are pay-per-use, and some are monthly fees based on a limited amount of fax pages you send or receive. You would have to evaluate how many faxes you expect to send and receive to determine if this is of value to you.