Boost in connection speed.

Surprised to see that my Mum's ADSL connection is now connected at the fastest speed it ever has. The attenuation has also dropped from 72db to 69db @300khz.

http://dl.dropbox.com/u/28466011/dmtm20130113_1735.png

I wonder what has been changed.

Edited by deleted (Sun 13-Jan-13 17:54:34)

Has the modulation changed from ADSL2 to g.dmt?

No it is still standard ADSL (992.1 Annex A) always has been.

It's with eclipse and they won't let us migrate to ADSL2+ unless we sign up to a new contract at a higher price (even though 21CN wholesale is cheaper to provide).

ADSL2+ won't work at that attenuation.
Has the line gone down for a while, indicating the E-side or D-side pairs have been changed?

There was a disconnect on the 6th Jan - http://www.thinkbroadband.com/ping/share/e33dc75f036...

Another on the 7th - http://www.thinkbroadband.com/ping/share/82a5265461c...

Both at times I wouldn't expect a BT engineer to be working at the PCP, could have been a change within the exchange but doesn't really look like enough down time.

There's something very strange about the minimum and average latencies there. It drops almost imperceptibly after the first disconnection but apparently has jumped considerably one minute later - at the start of the 7^th.

Independent of that, has the router been moved at their house?

Nothing has changed with regards to the set-up of the router, it''s location, the cable or anything else within the property.

Here's a ping graph for a day when no one was home (so no usage causing spikes in ping) - http://www.thinkbroadband.com/ping/share/4a1e4a44c6c... (This was before the higher sync)

I see what you mean about the ping changing at midnight, I had to flick between the two days to notice it.

I found an old DMT image from when I used to run with a 3~3.5db SNR Margin.

https://dl.dropbox.com/u/28466011/olddmt.png

This was one of the best speeds I'd had before with a 6dB SNR Margin it would normally run at around ~1200kbps, usually just enough to give a 1Mbps line profile.

The biggest difference between now and then is the recent use of some lower tones (frequencies) for the downstream. It also has some higher tones and generally more bits per tone over all.

Have BT changed the frequencies they use slightly?

Is it in an FTTC enabled area?
Maybe more and more ADSL customers moving over to FTTC is reducing cross-talk from the ADSL lines which still go all the way back to the exchange?
Your Mum has certainly gained a few extra frequencies AND the signal strength of the lower ones has increased, too.

EDIT: There is one very noticeable difference - see the closed gap between upstream & downstream frequencies?

Edited by adebov (Sun 13-Jan-13 22:28:45)

No FTTC but there are some people with Fixed Wireless (Vfast) or FTTH (the failed, but still running ICS project) now. So a good number of people might have ditched their ADSL service.

That might have made a difference but I think unlikely.