ADSL2+ on a Loooong Line - DAY 1

[imjolly]

with your attenuation of 63 you should still be able to get about 2mb connection speed on adslmax or adsl2

[KevG123]

Unfortunatley, real downstream attenuation is 72.8db which I think means I'm lucky to even get a connection

[imjolly]

should have read the previous posts - remember now

[KevG123]

No problem

You guys must read so many posts every day

[chris6273]

---

@imjolly wrote:

with your attenuation dropping by 2db maybe you have had a 'lift & shift' and got a better connection   with your long line adsl2 doesn't really matter and more importatnt is you seem to have a better faster conenction

---

Could have been the change from the old Alcatel DSLAM to Huawei (Infineon) MSAN in the exchange as two different manufacturers probably churn out slightly different readings.

The reason your downstream sync is higher is probably because of the slightly lower attenuation and because of the new Training Period you are on once you have been switched to different kit in the exchange. If you were on a 9dB Target Noise Margin profile on the Alcatel, the Infineon DLM will be trying the 6dB profile first to see if your line is stable with it (It did with me) which means a speed increase.

I'll be interested in seeing how ADSL2+ performs on your line because while it offers double the download bits and frequency band which can sometimes see a small speed increase on long lines, it has a much more aggressive DLM (As discussed previously in the thread).

Edit: I'm not sure whether the 21CN DLM has the ability to do so, but is there any chance it could have intentionally set the modulation to ADSL (G.DMT) because your attenuation is so long? It has been known to switch automatically to ADSL2 on some lines if they are long.

I hope the connection works out for you.

[imjolly]

you don't need to be on a long line for the change from adsl2 to 2+ and back again and again.  the quality of your connection and amount of noise can cause the switch from 1 to another - from personal experience

[john46]

and that was brought me to the forum to ask about

[chris6273]

Ah right I see, I wasn't sure how the DLM changing the Modulation works. 

KevG123 may just be seeing the situation we have seen many times before where customers are upgraded to 21CN but are left on standard ADSL.

Any idea what causes this? Surely unless it's intentional (and if its the situation), the MSAN should by default offer all modulations to the line?

[imjolly]

there are posts on the forum with attenuation the same but with modulation of 992.3/992.5 so line length cannot just be the reason.  it is possble that it has just not been upgraded yet

[john46]

that i have to say is my feeling