Thanks for letting us see the test results. I think the best possible form of action is gathering the evidence in case its needed.
Im not sure which chipset the Zyxel 3300N uses, so unsure of compatability with either DSLstats or routerstats. You could try
routerstats lite. These tools monitor your connection and log items such as the SNRm which can often give us a good indication of any faults on your line.
The 2nd bit of information which may help your cause is getting the results from the
BT FTTC availability checker. It may also be worthwhile putting in a neighbours phone number for comparision with yours just in case it picks up that youve been banded.
As regards to your ISP, as Blacksheep says, then at first you will have to go through the process. It wont harm to say something along the lines of "Due to the length of time my IPprofile has been restricted to 2Mbps, I suspect my line may have been banded by the DLM"
It is also worthwhile mentioning to them that you have bought a new router which shows a sync rate of 2.07/0.5 Mbps, yet the line has 24dBm of SNR indicating speeds up to 18.5 Mbps should be possible.
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To be perfectly honest I think there is something else going on with your line. The fact that the upstream IPprofile is 2Mb yet your line only syncs at .5 Mbps makes me go hmmm. Youve only got 6dB of SNRm on your upstream which to me suggests either something wrong with the internal wiring, a faulty filter (there was a bad batch of VDSL filters) or a physical problem with your actual telephone line.
I would also suggest doing the quiet line test to see if you can hear any audible noise on your line. (Dial 17070 and select option 2)
If you can get one of the above router monitoring tools to work that would also be good.
I think perhaps an engineers visit may be needed, but the more info you have beforehand about your line adds ammo to your belt. Only a BT openreach engineer can get the DLM reset and any banding removed.
Your line attenuation data is also interesting note how U0 is at 9.8 dBm, yet U1 is at 69dB and U2 at 67dB. This 'could' indicate that something within those frequencies is interfering with your dsl signal from the band frequencies of U1 upwards. This is unproven though because aside from U0 and D1 none of the other bands are in use so there's no bitloading outside of those bands. I wouldnt expect U1 to be more than U2 though. The fact that U1 isnt in use is likely why your upstream is so low.
