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Stuck on G.DMT?

Preserver
Newbie
Posts: 4
Registered: 13-10-2014

Stuck on G.DMT?

Hey all,
When using another provider I had the option to sync my router using ADSL2+ on the 21CN network. I then moved to BT and was put on a G.DMT service probably for stability reasons. I would like to switch back to ADSL2+ if that's possible?  I have a friend who lives nearby who recently also moved back onto ADSL2+ and get's better sync speeds as a result. I've only been migrated over a few days, do I need to wait for any line settling period?  or does that not matter on a migration?
Many thanks for any replies.
13 REPLIES
Community Veteran
Posts: 38,460
Thanks: 1,027
Fixes: 62
Registered: 15-06-2007

Re: Stuck on G.DMT?

While we are  waiting for this to be picked up by staff tomorrow can you help a little
Can you post the stats from the router - noise margin, speed and attenuation
What does this say about WBC on 21CN http://usertools.plus.net/exchanges/
A migration is normally like for like and the only reason you are on G.DMT is usually because you are on 20CN as a Plusnet router would usually report it as being ITU-T G.992.1 or 2 or 3 if you were on 21CN
Community Veteran
Posts: 26,637
Thanks: 868
Fixes: 10
Registered: 10-04-2007

Re: Stuck on G.DMT?

The TG582 reports this on 20CN:
Quote
DSL Type: ITU-T G.992.1
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
Broadband: Andrews & Arnold Home::1 (FTTC 80/20)
Line rental: Pulse 8 Home Line Rental (£13/month)
Mobile: iD mobile (£4/month)
Preserver
Newbie
Posts: 4
Registered: 13-10-2014

Re: Stuck on G.DMT?

Exchange info :-
Colour: Green 20CN VP capacity at this exchange is currently showing as Green.
Click here for further details
Colour: Green BT have advised that this exchange is enabled for WBC on 21CN
Colour: Unknown You can view recent Service Outages for this exchange here
Colour: Unknown BT have published Max DSL upgrade information for this exchange
Click here for further details
Line Stats - I use my own Draytek router, set to multi mode so will pick up whatever is offered, currently G.DMT but I have seen it on ADSL2+ with other providers.
Mode State   Up Speed    Down Speed  SNR Margin Loop Att.
  G.DMT SHOWTIME     480000             1984000           4                   62
Community Veteran
Posts: 38,460
Thanks: 1,027
Fixes: 62
Registered: 15-06-2007

Re: Stuck on G.DMT?

Is it actually 480,000 or 448,000
If 448 then you are definitely on ADSL1 but whether you are on 20CN or 21CN only Plusnet can definitely say
@Jelv
Thanks - in the dim and distant past on 20CN it was reported as G.DMT although I have no idea which router I was using at that time
Community Veteran
Posts: 5,059
Thanks: 426
Fixes: 16
Registered: 10-06-2010

Re: Stuck on G.DMT?

It's quite likely you're on 21CN ADSL1 with uncapped upstream. Plusnet tend to keep longer lines on ADSL1 with the fairly tautological reasoning that they might perform worse on ADSL2+. Of course saying they might be worse on ADSL2+ is always true, but you could just as easily say they might be worse on ADSL1 compared to switching them to ADSL2+.
In my experience, ADSL1 might achieve the highest line speed, but ADSL2 has better error correction. My exchange doesn't seem to do an auto fall back from ADSL2+ to ADSL2 so I get a better speed if I select ADSL2 at my end rather than leaving it on auto which ends up on ADSL2+.
Community Veteran
Posts: 26,637
Thanks: 868
Fixes: 10
Registered: 10-04-2007

Re: Stuck on G.DMT?

Running the BT diagnostic speed test gives a definitive answer. If it reports downstream only you are on 20CN, if it reports both up and down you are on 21CN.
Edit: Example of 20CN test attached - I'm on Max Premium hence the faster upload.
jelv (a.k.a Spoon Whittler)
   Why I have left Plusnet (warning: long post!)   
Broadband: Andrews & Arnold Home::1 (FTTC 80/20)
Line rental: Pulse 8 Home Line Rental (£13/month)
Mobile: iD mobile (£4/month)
Community Veteran
Posts: 19,100
Thanks: 437
Fixes: 21
Registered: 31-08-2007

Re: Stuck on G.DMT?

You beat me to it  Wink
PeeGee
Aspiring Pro
Posts: 1,086
Thanks: 47
Fixes: 3
Registered: 05-04-2009

Re: Stuck on G.DMT?

Quote from: ejs
My exchange doesn't seem to do an auto fall back from ADSL2+ to ADSL2 so I get a better speed if I select ADSL2 at my end rather than leaving it on auto which ends up on ADSL2+.

A quick check on the frequency "bins" in use would be a good indicator. My 61.9dB line (4.53km) seldom used bins above 150, so didn't get anywhere near the additional ADSL2+ bins, and achieved highest sync and data rates by forcing/selecting ADSL2*. ADSL2+ was next to unusable on my line, due to errors causing repeats and line drops.
Phil
* I was only able to "compare" with 20CN ADSL1 as I could not get ADSL1 to work when moved to 21CN - it would repeatedly appear to sync (based on lights) and then immediately drop the connection Roll eyes
Plusnet Fibre (Sep 2014), Essentials (Feb 2013); ADSL (Apr 2009); Customer since Jan 2004 (on 28kb dial-up)
Using a TP-Link TD-W9980 modem-router.
Community Veteran
Posts: 19,100
Thanks: 437
Fixes: 21
Registered: 31-08-2007

Re: Stuck on G.DMT?

I think it's probably a case of suck it and see with a lot of very long lines, and a lot can depend on the chipsets involved at the exchange as well as the modem/router and its firmware. Whilst on paper ADSL2 would seem potentially beneficial, I've seen cases where there wasn't the stability and it needed to set to ADSL1.
Preserver
Newbie
Posts: 4
Registered: 13-10-2014

Re: Stuck on G.DMT?

Pic attached, I am on 21CN.  Ignore the terrible speeds, multiple things were running at the time  (skype etc.)  usually get speeds that match my IP profile.
I think it would be worth giving ADSL2 a try as I never had any major issues when I was on it before but there is something to be said for stability over speed.  I guess it really is a case of suck it and see!  Do I need to wait for a mod here to pick it up?  or chuck a ticket their way?
Many thanks for all the useful replies so far.  Great community  Smiley
Community Veteran
Posts: 19,100
Thanks: 437
Fixes: 21
Registered: 31-08-2007

Re: Stuck on G.DMT?

It won't be a mod, they are customers just like you and I. It will be one of the CRT (Customer Relations Team), they'll probably pick it up tomorrow.
Hey and I see we all forgot to say welcome to the forum  Wink
JTaylor
Grafter
Posts: 93
Registered: 18-08-2014

Re: Stuck on G.DMT?

Morning Preserver
I've had a glance over this for you and placed the right orders to move you onto ADSL2+. The orders should complete within 24 working hours.
I hope this helps but if you have any more bother with this get back to us.
Preserver
Newbie
Posts: 4
Registered: 13-10-2014

Re: Stuck on G.DMT?

Thanks for this, upload speeds much improved as a result which really helps with the two of us using the connection on an evening!