Connectivity issue

As an I.T guy i get to see some strange issues but this has dumbfounded me, so i'm posting on here to share my experience and ask for any input as someone else may have had the same issue.

Scenario
AOL broadband that has been in use for 2 years. The telephone/broadband cable was moved from the house to the business premises by BT some 5 months ago at great expense.( the house no longer is connected to this line)

So here we have a new line with AOL running on it but never tested until now... keep with me here..
I installed the Netgear DG834PN ADSL router the customer used in the house to connect, so no re-configuration necessary. However the line would Sync but not authenticate. A few calls to AOL later and i have confirmed the username and password which still failed - faulty router i thought.

I installed a Speedstream 4101 (supplied by Tiscali), added the username and password and hey presto! it works..

Brought a DG834G, the Mondeo of routers and supported by AOL, but this also failed. I have since tried this router on my home connection and its ok.

I then thought chipset compatibilty or exchange fault!? so i went and bought a white box ADSL router - this also fails.

So here i have a broadband connection which works with a Tiscali Speedstream router (really bog standard) but not with any other router so far..

I have tried amending vpi/vci settings PPPoE llc/vc settings in all combinations to get the other routers working to no avail.
Any ideas anyone?

Greg

Do you have any logs from the failed auth ?

...and the sync rates/error rates etc, are the same when the various routers are in sync ?
Is it BT Wholesale based AOL stuff ?

hi.. sync rates, snr ratios are al the same with varios routers. I don't understand why a simple router such as the speedstream works yet no others seem to.

looking into the logs, its jus the username and/or pwd not being authenticated, even though they are the same.

In reply to a post by GregW:

looking into the logs, its jus the username and/or pwd not being authenticated, even though they are the same.

So they're not the same.