Telecom NZ – setting up a DSL-502T router to avoid drops

I am writing this “how-to” article on December 16th, 2006. Be aware that this ‘solution’ may have a limited shelf-life and it may not be applicable to everyone’s DSL drop problems with New Zealand Telecom.

Be warned also, that I take ABSOLUTELY NO responsibility for the results or problems that may result if you decide to try this solution and it doesn’t work out well. If you don’t feel confident enough to do this and to take notes along the way so that you can gracefully back out again if it doesn’t work – do not proceed and most certainly, do not contact me for help. Other than providing this information and asserting that this solution has worked cleanly for myself and at least one other person, I will NOT be further involved.

Background: If you read the following sources, you will be up to speed on what the problem is that this solution deals with:

Geekzone thread




Applicability: If you are experiencing drops such as those described above, then this ‘fix’ may help you. Note, this problem seems to be related to physical hardware in the distribution exchanges. It probably do not matter which ‘plan’ you are on or even which Internet Service Provider (ISP) you are using. If your signals pass through an exchange with this particular issue, then you are likely to have the problem, regardless.

The Fix:

There are many things you can screw up by experimenting with the settings within your ADSL Router. I advise you not to ‘step off’ the beaten path here unless you are very brave or knowledgeable. If anything isn’t the way I’m describing it or as you expect, just back out gracefully.

– access your DSL-502T ADSL Router’s setup software by directing a browser to

– You should be presented with a User Name / Password challenge. Enter ‘admin‘ and ‘admin‘.

– Choose the Tab along the top labeled, ‘Advanced‘.

– Choose the Tab along the side labeled, ‘ADSL‘.

– Your modulation type should be set to ‘ADSL2+ (Multi-mode)

– Change it to ‘ADSL (ITU G.992.2)

– Click on ‘Apply

– Choose the Tab along the top labeled, ‘Tools‘.

– Choose the Tab along the side labeled, ‘System‘.

– Click the ‘Save and Reboot‘ button

The DSL-502T will reboot now. Dismiss your web browser as we are done with it. Be patient for a bit after it reboots. For several minutes after I did this, I thought it didn’t work because I still experienced drops. But after a few minutes, I think the 502T and the exchange agreed on the new protocol and everything smoothed out. Since then I’ve had zero drops.

Postscript: Telecom is not advertising this fix. Indeed, I don’t even know if they know of it. But, I suspect that if they do, they would not advise it anyway because their real goal is to get all of their gear working correctly with the setting they’ve chosen which is the ADSL2+ (Multi-Mode) setting. If zillions of people switch off onto the ADSL (ITU G.992.2) protocol whilst Telecom’s deep into trying to debug their current problems, it’ll probably just add confusion to the situation from their POV. So, my recommendation is, for everyone’s sake, that you switch back to the original ADSL2+ (Multi-Mode) protocol every few days to see if Telecom has gotten things sorted out. And, if you do have occasion to talk with them about DSL technical issues, I would certainly not tell them you are running a non-standard protocol as they will probably just choose to not deal with you if your equipment is not setup in their standard and expected fashion.

Downside: According to the fellow who discovered this fix, your upload and download speeds will be a bit slower using the new protocol. Personally, I can live with that in exchange for a solid connection that doesn’t drop me.  I’m seeing upstream at 160 kbps now and downstream at 2565 kbps with the fix running.
Thanks: My thanks to Neil up Auckland way for taking the time (and being brave enough) to muck about with all of these various protocol settings until he found one that seems to work in spite of Telecom’s current drop problems in the exchanges.

Addendum on 061222 -  There have been some questions raised when folks with modems other than the ADSL Router DSL-502T have wanted to try this fix.  When they’ve looked at their options within their local modems, they haven’t found the ADSL (ITU G.992.2) option that exists within the 502T.

Well, I believe that the ADSL (ITU G.992.2) configuration may be equivalent to an ADSL_G lite configuration.

I say this because now that my 502T is running the DSL (ITU G.992.2) configuration, if I go to Status > ADSL in the 502T, it says that ‘modulation’ type is ADSL_G lite.


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