Netgear DGN3500 guide

Photo of the NETGEAR DGN3500

For those looking for an ADSL wireless N gigabit router that is cheaper than the Billion 7800N, the NETGEAR DGN3500, using modified firmware, allows you to tweak the SNR margin.  You can buy the NETGEAR DGN3500 modem at a great price.This page provides the NETGEAR DGN3500 manual and links to independent reviews. We provide information on how to tweak the SNR target margin, to maximise your broadband speed, by using modified firmware.

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NETGEAR DGN3500 user manual

The Billion BiPAC 7800N user manual (in PDF format) can be downloaded or viewed by clicking the link below:

NETGEAR DGN3500 user manual

NETGEAR DGN3500 reviews

Here are links to recent reviews of the NETGEAR DGN3500:

Expert Reviews review of the  NETGEAR DGN3500 (August 2010)

PC Advisor review of the NETGEAR DGN3500 (September 2010)

Official NETGEAR DGN3500 firmware

 The latest ‘official’ firmware can be obtained from the link below:

Official firmware for NETGEAR DGN3500 ( (worldwide)

Modified firmware allows you to tweak the SNR margin

Modfs is a firmware modification that resides on a USB drive connected to the NETGEAR DGN3500 router, which is aimed at extending the features of the original router firmware. Of particular significance, the Modfs modification provides the ability to tweak the SNR target margin. 

As discussed in our SNR tweaking page, tweaking your SNR target margin could more than double your downlink connection speed. 

You can download the modified firmware and find instructions on this page.

According to Dan Leigh (who alerted us to this firmware):

“I’d never risked using custom firmware on a moden/router before, thinking that if anything goes wrong, recovery may not be possible. This Modfs firmware is not like other custom firmware. It is not a complete firmware replacement. It’s mainly a single file on a USB stick in the back of the modem.

“There is a firmware update to perform, but it’s just Netgear’s original firmware that has been slightly modified to tell the modem to boot the Modfs file on the USB stick. “

Use “” to access the new Modfs interface. You can still access the modem’s graphical user interface (GUI), too, and you can also have both interfaces open at once.

On the Setup Page, Main tab, is a setting named Target SNR Margin (%). You can work back from 100% in gentle steps over a period of a few days to determine the optimum setting. 

Please let us know if we have helped you!

If the information that we have provided has helped you to significantly improve your broadband speeds, then we’d love to hear from you. Please email us at