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WinFax, Super G3 and the speed of fax.

Why are faxes so slow to complete when sending or receiving?

This is a common question that isn’t always easy to answer without more details on the specific fax pages you’re actually sending or receiving. There is a possibility that transmission errors  can cause pages to be re-transmitted, increasing the overall send and receive time.  In addition, there are compatibility issues with specific types of fax devices, where the maximum fax speed may be limited due to different fax specifications such as v.34, v.32 bis and v.17 (more on this later.)

WinFax and the maximum fax transmission and reception speed.

The truth is, all fax transmissions are slow when compared with today’s high speed internet. The maximum speed you can receive and send with WinFax PRO is 14.4 kbps (14,400 bps), regardless of the type of fax modem you use.  This is a fax specification that is called v.17. You can send a 50 page Word document via e-mail in seconds, while that same 50 page document would take almost an hour to fax using a v.17 fax.

Super G3 and v.34 fax

Some newer office fax machines support something called Super G3 (also called v.34bis), and an older fax standard called v.34, both with transmission speeds of 33.3 kbps and 28.8 kbps respectively.  However, most  consumer grade fax modems that you buy for your computer don’t support Super G3 or v.34.

Both Super G3 and v.34 fax are not supported by WinFax PRO, even if WinFax did support the newer Super G3 standard, chances are you don’t have the fax modem hardware to be able to take advantage of it. Super G3 is usually reserved for higher-priced office fax machines and higher-end fax modem cards.  Usually, large and medium sized businesses may have a Super G3 Fax machine, but many are still using fax machines and devices that support the older v.17 standard at 14,400bps.  About 3 out of 10 fax machines support the Super G3 specification.

If you use a Super G3 Fax, your maximum speed is 33.3k bps — that’s less throughput then standard telephone based dial-up internet access! Now that’s not so Super speed, but it does cut the transmission time in half when compared to v.17 fax, and also the initial connection and disconnection times are reduced in Super G3 Fax.  To see the benefits of a Super G3 Fax machine, you must communicate with another Super G3 Fax machine or compatible device.

The good news is its all compatible, so a Super G3 Fax Machine can talk with other types of fax machines, including a WinFax equipped computer. The lowest speed of the two machines fastest speed is the transmission speed that is set during the initial connection.

Average time to send or receive a fax page

The time it takes to send or receive a fax is based on the actual content of the fax, and how that fax is compressed during the transmission. On average, a single page will take approximately 1 minute to transmit at the WinFax maximum 14.4kbps speed (about 1/4 the speed of the fastest dial up modem internet connection).

That time will increase considerably if the fax image includes photographs, or complex images on the page. A fax with continuous white-space can be sent or received much faster when compared to faxes with a lot of text and graphics, usually a single fax page with a lot of white-space can be transmitted under 45 seconds. A lot of this time is consumed at the initial connection, start of a new page, and disconnection portions of the transmission.

How to speed it up

If you are concerned about the time it takes to send a fax. I recommend reducing the quality of the fax transmitted by sending pages in “Standard” or “Low” resolution. This can be configured in WinFax setup, under the Send options. This can reduce the sending time of faxes by as much as 50%, but the quality of the fax that is received on the other side suffers. If you use a Class 1 fax modem, you can also turn on the High Speed and 2D Compression options.  You do not have this option with a modem configured as a Class 2 or 2.0 fax modem in WinFax PRO.

When receiving faxes, you do not have control how they are received, if a fax is transmitted by the sender to you in high resolution, you will receive the fax in high resolution and it may take additional time to receive it. If two 14,400 bps machines are connecting, the entire fax transmission speed should be 14,400 bps unless there are some problems with the connection. Speeds such as 9,600 bps, 4,800 bps and 2,400 bps are also possible during error conditions. There are also 9,600 bps fax machines, so you may be receiving from an older fax machine where the maximum speed is 9,600 bps and it may be a normal condition.


Faxes are slow when compared to today’s high speed internet access, regardless of the fax specification you’re using.  There is nothing you can do about this limitation. Computers don’t normally come bundled with a fax modem that support Super G3 (Class 2.1 type fax modem), so you can’t take advantage of the speed increase unless you spend money on an expensive fax board and use software that will support the Super G3 specification.

At the time of the writing of this article, we found a reasonably priced hardware based internal PCI and PCI express fax modem that also supports Super G3 (Class 2.1), the MultiTech Multimodem ZXP.   Multitech has been in the fax modem business for many years, and are known for reliable products. They are one of the few manufacturers that produce an internal Super G3/Class 2.1 fax modem.

UPDATE: We have a limited supply of Super G3 USB Fax Modems by Multitech available:

If you use this fax modem with WinFax, it will not support the Super G3 fax setting, you will have to configure this fax modem as a Class 1, Class 2, or Class 2.0 fax device.

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