OP here. All these different results from different people = mindblown.

From another forum I saw these results. - http://forums.whirlpool.net.au/archive/1403140

Billion 7800N (firmware 1.02g)
PPPoA VC-Mux
Sync: 16296/1843
Att: 27dB/18.5dB
SNR: 5dB/6dB
Profile: High Speed Annex M

Billion 7402GL (5.54b)
PPPoA VC-Mux
Sync: 16713/2254
Att: 27.5dB/19.5dB
SNR: 5.5dB/6dB
Profile: High Speed Annex M

I have pretty much the same stats as them but a different router performs better. I suppose this makes sense with me dropping 4.5 db with a different router. But basically, my SNR also affects the speed so I should contact my ISP and be put on a 3db profile? My router is solid at 6 so may aswell try it. But from what you guys have posted, even if I have 23.5 db download attenuation on a 3db profile I might not even get an extra 1kbps on Annex M.

Technology is incredible!

One thing to try first, if you haven't already, is to see what connection speed you get by plugging the router into the Test socket, on the wall at the back in this pic. Just use a short ADSL cable though, not a plug-in extension.

You might get over 2Mbps more than now, and that would put you well over the cutoff point and make it worthwhile. We would just have to talk you through getting the same speed when plugged in normally.

Yeah, it was directed to you, I was letting you hear my experiences with Annex M as you answer a lot of these questions.

Oh and I only router that I get the 2450 sync on is my Netgear DG834G (v3), it lowers the upstream snr to 4 or 5.

All the other routers that I have sync at 2000kbps.

Here's those routers:

Netgear DG834GT
Billion Bipac 7800n
TP-Link TD-8816
Huawei EchoLife HG532
BT 2700HGV
Sagem F@ST 2504

Thanks .

You know, I would have thought there was a sure fire way of working this out (quite accurately), unless there's some magical difference between downstream and upstream attenuation I'm not aware of.

My theory goes like this. Annex M uses more of the downstream BINs as upstream (double, as I understand it). So, if we have a modem that shows us how much data is encoded downstream in the BINs that will be replaced by Annex M for upstream, we can calculate both how much more bandwidth we're going to get upstream, and how much we will lose downstream.

Right?

Or am I missing something (that something maybe being that attenuation of a frequency (BIN) on a line can vary depending on the direction the signal is travelling, eg. upload or download) ?

Should I go and purchase a v3 DG834G or is there better routers on the market now?

Annex M causes the attenuation to increase.

In reply to a post by mixt:

You know, I would have thought there was a sure fire way of working this out (quite accurately), unless there's some magical difference between downstream and upstream attenuation I'm not aware of.

My theory goes like this. Annex M uses more of the downstream BINs as upstream (double, as I understand it). So, if we have a modem that shows us how much data is encoded downstream in the BINs that will be replaced by Annex M for upstream, we can calculate both how much more bandwidth we're going to get upstream, and how much we will lose downstream.

Right?

Or am I missing something (that something maybe being that attenuation of a frequency (BIN) on a line can vary depending on the direction the signal is travelling, eg. upload or download) ?

The main thing you are missing is that the loss of download from the lower frequencies can be compensated for by increased use of the higher frequencies on shortish lines. On longish lines, ie only giving around 16Mbps on Annex A, those higher frequencies are already at capacity due to higher attenuation.

I tried to explain it simply starting at paragraph 3 of this post.

I also said there I don't quite understand why upstream doesn't gain the full amount of those lower frequencies that are nicked for it.

As usual Batboy, another single line response claiming to be the be all and end all of an accurate answer.

Please cite your claim. What you are suggesting is that Annex M (which is purely an ADSL standard, nothing more) changes the physical characteristics of the line that it is operating over, which is impossible.

You probably mean to say this: it causes the attenuation to increase because the amount of bandwidth available to the downstream part of the signal decreases because we are sacrificing good quality lower frequencies for upstream utilisation. This has a negative impact on the measurable attenuation of the downstream spectrum. Upper frequencies inherently have higher attenuation than lower frequencies, so the measured attenuation appears to be worse, however, the actual physical attenuation of the line has not changed.

I've had a sherry this evening, so excuse me if I come across quite blunt when I say this - but for a guy who is ranked as 'Legend' on these forums, with a post count of 17,610, I think this forum should introduce an additional user statistic which is the average number of words per post (excluding any words in posts that are enclosed by quote tags). This would really show up the one line posters like yourself who, in my view, bring very little quality information to the forums.

Right, I'm away for another drink.

Gotcha, and fully understood.

Maybe the exchange can transmit the signal with more power (downstream) than the modem can send (upstream) ?

Purely speculation.

Edited by deleted (Sun 16-Oct-11 21:36:55)