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How can I tell if I am on ADSL2 or not...(and other problems!)

grahamn
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Registered: ‎12-09-2010

How can I tell if I am on ADSL2 or not...(and other problems!)

Hi,
As per subject, I'm wondering how I can tell as we were supposely migrated across 21CN on the Portishead exchange last month.
I discovered this when our web browsing came to a halt - (curiously akin to losing DNS)... sync and connection was there at 8Mbps but not a lot else. Changing the router from G.DMT ADSL2 or 2+ (G992.3 or G992.5) or multimode (i.e. auto) picked up ADSL2+ and conection and browsing worked once again. So far so good, however......
So having had a disconnect recently whilst on "auto" I was surprised to have problems browsing again, so checked the router status. It was showing G.DMTas the  ADSL mode again. Double checked the setting - it was multimode - so I would've expected it to pick up the ADSL2 modulation...but it hadn't. Manually forcing it to 2 or 2+ works but with a very marginal snr margin of between 1.5 and 3.0 and a high uncorrected error count.
So, does the router not auto-negotiate with the DSLAM and get the "best" modulation going or am I not on 21CN/ADSL2 for some reason?
I seem to have a choice between G.DMT, syncing at 8Mpbs and a SNR margin of 5 but this only works a short time or, syncing at 10+ and geting a very marginal SNR of betwen 1.5 and 3.
Prior to21CN  "migration" we were rock steady at 7Mbps sync and SNR margin of 6

14 REPLIES 14
grahamn
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

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spraxyt
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

If you carry out a diagnostic test on the BT speedtester and it does an upload test that will confirm you are on 21CN. However your service could still be set to ADSL1. It would be unusual for multimode to end up with ADSL1 if ADSL2 or 2+ is available.
David
grahamn
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

BT Speed tester does do an upload test, so presumably 21CN? That being the case, it seems odd that the router auto selects G.DMT, unless the SNR margin is not enough? What should that be for a good 21CN connection?
Anotherone
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

I think you need to post the full ADSL stats from your modem/router to give us some idea of what is going on. Has your modem/router got the latest firmware, it's possible that it may not be handling ADSL2+ properly. Or, you may have developed a line fault!
MrC
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

Similar issue here and it would be nice if BT or PN could show somewhere exactly what flavour of ADSL is configured on a line from the exchange perspective.
Many months ago I asked for our line to be ADSL2+ enabled and was assured several times that it had been done but the modem/router (TG585v8) always negotiates ADSL and never ADSL2 or 2+ (and yes it's got the latest PN firmware and is set to negotiate ADSL2+  Smiley ). Admittedly the line has a high downstream attenuation of 57.5dB but the error count and SNR margin variation is really low considering the line has been up for just under 4 months so am surprised that we don't see at least ADSL2 :-
mike=# select to_char(date,'YY/MM/DD HH24:MI:SS'),band_dn,band_up,snr_dn,recv_fec,recv_crc,recv_hec,frame_loss,signal_loss,errsecs from tg585v8 where (date > '11/11/12 13:40');
      to_char      | band_dn | band_up | snr_dn | recv_fec | recv_crc | recv_hec | frame_loss | signal_loss | errsecs
-------------------+---------+---------+--------+----------+----------+----------+------------+-------------+---------
12/11/11 13:40:01 |    2368 |    448 |  7.000 |  9024337 |    34726 |  181439 |          0 |          0 |      37
12/11/11 13:42:02 |    2368 |    448 |  7.000 |  9024359 |    34726 |  181439 |          0 |          0 |      37
12/11/11 13:44:01 |    2368 |    448 |  6.500 |  9024360 |    34726 |  181439 |          0 |          0 |      37
(3 rows)
mike=# select max(snr_dn),min(snr_dn) from tg585v8;
  max  |  min 
-------+-------
7.000 | 6.000
(1 row)
Anotherone
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

As spraxyt posted earlier, if you run the BT Diagnostic Speedtest, if it runs an Upstream test then you are on 21CN. Exactly what you get will depend on connection quality and internal wiring if the latter is not up to scratch.
MrC
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

Quote from: Anotherone
if you run the BT Diagnostic Speedtest, if it runs an Upstream test then you are on 21CN.

Has that changed as I'm sure I can remember the BT Speedtester in a previous incarnation performing an upstream test on 20CN? Could just be my memory playing tricks tho' !
jelv
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

I'm still on a 20CN only exchange as was the exchange I was on before I moved and I've never seen an upload test when running the BT speed test.
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 (£14.40/month)
Mobile: iD mobile (£4/month)
Anotherone
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

The standard BT Diagnostic Speedtest doesn't run an Upstream throughput test on 20CN.
MrC
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

Thanks for the updates guys. However being on 21CN doesn't mean that the line will automatically be provisioned for ADSL2+ though does it? In other words the BT speedtester can show an upstream test but you can still only have ADSL?
spraxyt
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

Yes you can still be ADSL1 (up to 8Mbps - old terminology) even on 21CN. Plusnet do use that but normally only where the expected sync speed is less than 4Mbps. Below that point ADSL2/2+ is unlikely to be of benefit and can result in sync speeds lower than ADSL1.
David
Anotherone
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

@MrC
Provisioned or not, it doesn't always give a benefit and can sometimes result in an unstable line. Your line seems to be just at that awkward length where ADSL2/2+ is not likely to give any improvement. Leaving that aside, your line seems to be underperforming.
Can you hear any crackling or other audible noises on the line when using the phone? Have you had any other problems with incoming or outgoing calls?
Do you have an NTE5a Master Socket and are you using Microfilters that look like this?
Do you have hard wired extension sockets? Is everything plugged in connected by filters? Are you using any plug in extension leads of any type, if so where?
MrC
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

Thanks for the reply. The router/modem is plugged directly into the test socket of the NTE5 because of poor quality extensions, and the line stats don't differ if I remove the only phone (an old BT Freestyle cordless). The phone does hiss on a 17070 quiet line test but I need to source another test phone to check whether it's the handset or the line itself. Having said that the error counts reported by the TG585 are far lower and more stable than a number of other much lower attenuation lines I've used and I've wondered if it would be worth requesting PN to lower the SNR margin as the initial negotiation always results in a 12dB margin.
To be honest the main reason I'd like ADSL2 is for an improved upstream bandwidth.
Anotherone
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Re: How can I tell if I am on ADSL2 or not...(and other problems!)

If you could post your current modem/router ADSL stats, which as it's a Thomson 585, you will typically find here. Click on View more and do a copy and paste.
When you say that the stats do not differ when you remove the phone, the figure you need to be looking at is the Noise Margin. If the phone is having some effect the Noise Margin will increase when you've removed it.
You haven't confirmed that your filters are the "rat's tail" type similar to the link I posted.
You mentioned about poor quality extensions., I assume you've checked that they are all dead now you are plugged into the test socket. What colour wires and what terminal numbers are connected at the back of the front plate that you've taken off the NTE5a?