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Standard User meditator
(fountain of knowledge) Thu 27-Sep-12 16:37:49
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Billion 7800: possible to adjust UPSTREAM target SNR?


[link to this post]
 
I currently use a Billion 7800 ADSL router. Excellent device, at least on ADSL it is.

With this router I've long been able to punch in via the browser a specific target SNR setting of 12dB for the downstream side of things and this has kept things nice and stable for my long and noisy line to the exchange.

Is there a means of adjusting the SNR for the upstream side as well? But perhaps, due to the assymetry, you may not be able to adjust that side without affecting the other?

The reason I'm asking is that I've been automatically upgraded from ADSL1 to ADSL2+ (Annexe M) and unfortunately although this has raised my upstream sync from 480K bps to around 870K bps, it's been at the expense of a somewhat lower downstream speed. Also, the upstream's SNR has plummeted from about 15dB to 6dB. My line simply cannot operate stably at as low an SNR as 6dB.

If I'm to stay on this nominally 24M bps connection, it's going to be a matter of juggling the SNRs, and therefore the speeds, of the downstream and upstream paths, but I fear I may not have a choice in that. What hasn't helped, I think, is that I've been taken off Interleaved mode. I'm currently trying to get that put back on again.

I'm not worried about having a low upstream speed, ie. 480K, as I rarely upload any large files, but I want a decent downstream speed. Using the 7800, on ADSL1 I'd formerly achieved just over 5M bps downstream, together with the usual 480K bps upstream. Downstream attenuation is 51dB.
Administrator MrSaffron
(staff) Thu 27-Sep-12 17:12:07
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Re: Billion 7800: possible to adjust UPSTREAM target SNR?


[re: meditator] [link to this post]
 
if it really is Annex M, then tell the router to NOT connect using Annex M (though some TalkTalk lines I have found if you do this when Annex M is enabled will NOT sync)

A move from ADSL to standard ADSL2+ would have boosted your upstream to the speeds you suggest, hence why questioning annex M. Annex M usually only boosts upstream speeds on lines running at over 12 Meg.

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User meditator
(fountain of knowledge) Thu 27-Sep-12 17:53:02
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Re: Billion 7800: possible to adjust UPSTREAM target SNR?


[re: MrSaffron] [link to this post]
 
Well, the 7800 happened to have Annexe M enabled when the changeover to ADSL2+ occurred. My understanding was that the '+' meant that the upstream speed was specifically increased.

It sounds, from what you say, that having Annexe M enabled has been a waste of time in my case. I must say I was sceptical about having ADSL2 in any shape or form, given the length of my line, but I got given ADSL2+ by default.

I've since tried deselecting Annexe M and allowing the router to resync but that didn't make any difference; I'm still getting nearly a doubling of the upstream speed whilst getting around 0.5M bps less in downstream. And the upstream SNR is still tootling around at just 6dB.

My question really relates to whether there's a command string for this router to adjust the upstream SNR (upward in my case), even though that would then affect the downstream speed.


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Standard User XRaySpeX
(eat-sleep-adslguide) Thu 27-Sep-12 18:25:12
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Re: Billion 7800: possible to adjust UPSTREAM target SNR?


[re: meditator] [link to this post]
 
You are not on Annex M!

You don't get M w/out requesting it; it doesn't occur auto. Whatever your router says, it's for the exchange kit to decide as set by the ISP.

By switching off M at router and it doesn't make any difference conforms you are not on M.

EDIT: Post your full router stats incl. ADSL Mode.

1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 19 Meg WBC

Edited by XRaySpeX (Thu 27-Sep-12 23:20:24)

Standard User b4dger
(knowledge is power) Thu 27-Sep-12 18:46:24
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Re: Billion 7800: possible to adjust UPSTREAM target SNR?


[re: meditator] [link to this post]
 
As others are saying, I doubt you have Annex M this is normally a paid for option.

Looks like it's just a move to ADSL2+ that's causing issues.
Is your tweaked downstream TSNRM still working?

You may like to try forcing different 'modulations' (ADSL/ADSL2) if ADSL2+ isn't working well?

EDIT: I remember in the past that you didn't want to say who your ISP was - I've just had a (very) quick look at your previous posts and read that you were going FTTC earlier in the year. So it might be worth mentioning what your current package/setup is for people to advise? smile

Edited by b4dger (Thu 27-Sep-12 18:56:52)

Administrator MrSaffron
(staff) Thu 27-Sep-12 20:16:07
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Re: Billion 7800: possible to adjust UPSTREAM target SNR?


[re: meditator] [link to this post]
 
Dont know about command line tweaks for the router, BUT playing around with the upstream should not affect the downstream.

On ADSL2+ the two sets of frequencies are kept apart.

Only if Annex M is specifically enabled on a line do the two interact.

The + refers to the doubling of the frequency for the downstream speeds
The 2 refers to second standard of ADSL, with better maths
ADSL on its own always had the ability to run at 800+ on upstream, just was capped before. Going to the newer services they have uncapped the upstream.

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User RobertoS
(sensei) Fri 28-Sep-12 01:29:04
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Re: Billion 7800: possible to adjust UPSTREAM target SNR?


[re: meditator] [link to this post]
 
Please can we have a full set of stats from the router? Including the mode.

My broadband basic info/help site - www.robertos.me.uk
Domains,website and mail hosting - Tsohost. Connection - Plusnet Extra Fibre (FTTC). Sync ~ 56.0/13.9Mbps @ 600m.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.
Standard User meditator
(fountain of knowledge) Fri 28-Sep-12 13:02:57
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Re: Billion 7800: possible to adjust UPSTREAM target SNR?


[re: RobertoS] [link to this post]
 
No need to supply any stats, as in the meantime I decided to request the ISP to return me to the 8M bps service and to Interleaved mode. That's now been successfully done, so as far as I'm concerned the problem caused by the automatic upgrade no longer exists and therefore there's no need to ask any of you any longer whether it's possible to tweak the upstream SNR.

It was a bit unfortunate that the automatic upgrade to ADSL2 (24M bps) produced an awful result in my case, but the ISP wasn't aware of the long, flakey connection I'm on. It wasn't an upgrade by personal request, it was a mass upgrade. A move up to ADSL2 or ADSL2+ doesn't necessarily guarantee increased speeds. As ever, a lot depends on just how far away you are from the exchange (attenuation) and the amount of noise and crosstalk to which the line's subjected.

My thanks to all of you nevertheless for your suggestions and comments. Sorry to end it there but the job's sorted now.
Standard User RobertoS
(sensei) Fri 28-Sep-12 13:34:17
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Re: Billion 7800: possible to adjust UPSTREAM target SNR?


[re: meditator] [link to this post]
 
It's good to hear things are now OK.

The reason I asked for the stats was mainly to see what could be gleaned from them wrt confirming you were on Annex M or not.

My broadband basic info/help site - www.robertos.me.uk
Domains,website and mail hosting - Tsohost. Connection - Plusnet Extra Fibre (FTTC). Sync ~ 56.0/13.9Mbps @ 600m.

"Where talent is a dwarf, self-esteem is a giant." - Jean-Antoine Petit-Senn.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.
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