New Modem - possible tweaks needed?

Hi,

I just bought a new Billion 7800N and got it up and running with my ADSL2+ connection (BT). The status looks like this:

Parameters
DSP Firmware Version A2pB025f.d22k
DMT Status No Defect
Operational Mode G.DMT
Upstream 448
Downstream 5824
SNR Margin(Upstream) 19.0
SNR Margin(Downstream) 10.0
Line Attenuation(Upstream) 25.5
Line Attenuation(Downstream) 41.0

I'm not sure if these are good/bad/indifferent, or what I can do (if anything) to improve them. Can anyone check them over and give me some advice?

Thanks.

For starters you're not running on ADSL2+, on which you could get about 8 Meg.

No point in tweaking until you get on ADSL2+ and see what it delivers.

You sure your exchange (which one?) does ADSL2+?

I'm not?

The exchange is, yes. At least it's listed on BT Wholesale as being ADSL2+. It's Ely, Cambridgeshire.

Edited by deleted (Mon 16-Jul-12 20:46:40)

Definitely not on ADSL2+. G.DMT is plain ADSL, and the 448kbps upload is the norm for plain ADSL but pretty well never seen on ADSL2+. Check what the mode setting is in your Billion.

The downstream noise margin is also very high and costing a lot of speed. Have you done a lot of reconnections in a short time, trying to get it as you want? That could have caused it.

As XRaySpeX says, you should be connecting at approaching 8Mbps. ADSL2+ should be well over 8Mbps. What did you connect at before you put in the Billion?

Edited by RobertoS (Mon 16-Jul-12 20:53:39)

It's quite simillar to what it was before, just a fraction faster either due to the new modem or due to the new Cat 5e ethernet cable I bought (or both, or neither). All I've done recently is disconnect existing modem and connect the new one.

Settings for the mode page on the Billion look like this:

ADSL Mode: Annex M is checked.
Modulator: All of ADSL2, ADSL2+ G.Lite, T1.413, G.Dmt are checked
Capability: SRA Enable is unchecked
PhyR: Upstream, Downstream are both unchecked.

Ok just chatted to BT person and my profile is ADSL, although the exchange supports ADSL 2. According to the support person:

"Our test indicates that your line currently supports an estimated ADSL Max broadband line speed of 5.5Mbps; typically the line speed would range between 4.5Mbps and 6.5Mbps.

Our test also indicates that your line currently supports an estimated ADSL2+ broadband line speed of 5.5Mbps; typically the line speed would range between 3Mbps and 8Mbps."

That's a total fob-off, read from this site. Those figures are normally under-estimates.

Did he tell you why you aren't on ADSL2+?

Ah - yes, someone else recently got told they weren't on ADSL2+ because it wouldn't benefit them. Well in your case it would. The line stats tell us the truth about your line. That info is just from a known-to-be dodgy database.

Try putting your stats into this checker, then this one, and take a look at this graph and then this one. If you want to be cautious, on the graphs look at 44dB attenuation for the ADSL2+ figures, as you often find attenuation goes up by 3dB on a move from ADSL to ADSL2+.

Have a look at this page, particularly re G.DMT and ADSL2+. (On the right).

The default noise margin immediately after connecting is 6dB. Some time, reconnect and read the stats immediately. Better done in daylight though, (or repeated then if you do it now). You will probably get a lower speed at night that in the daytime.

My line:-

Our test also indicates that your line currently supports an estimated ADSL2+ broadband line speed of 3.5Mbps; typically the line speed would range between 2Mbps and 6Mbps. Our test also indicates that your line could support an estimated ADSL 2+ Annex-M broadband upstream line speed of 500Kbps and downstream line speed of 3.5Mbps; typically the downstream speed would range between 2Mbps and 6Mbps.

Our test also indicates that your line currently supports a fibre technology with an estimated WBC FTTC Broadband where consumers have received downstream line speed of 51.7Mbps and upstream line speed of 13.2Mbps.

6Mbps was normal for me on ADSL2+. My current FTTC connection speeds are 56626/14078kbps.

Edited by RobertoS (Mon 16-Jul-12 22:34:42)

Fascinating stuff. It looks like I can get a considerable boost from being given the ADSL2+ profile. It's not that I'm being fobbed off, more that I've been a customer for six years here and have never questioned it. Presumably they don't automatically upgrade people when they upgrade the exchange but would do for new customers.

I'll have to call sales then, to see what I have to do to get the correct profile.

In reply to a post by RobinsonUK:

"Our test indicates that your line currently supports an estimated ADSL Max ... typically the line speed would range between 4.5Mbps and 6.5Mbps.

Our test also indicates that your line currently supports an estimated ADSL2+ ... typically the line speed would range between 3Mbps and 8Mbps."

The top end of those ranges are most appropriate for your line. So ADSL2+ is beneficial for you over ADSL Max.

Remember your Down Attenuation will probably rise by 3 dB on ADSL2+.

Remember your Down Attenuation will probably rise by 3 dB on ADSL2+.

Sorry to divert the thread slightly, You say 'Downstream Attenuation will probably rise by 3dB on ADSL2+'. Is this dependent on how the router handles and reports the higher frequencies? I ask, because my Apple Airport Extreme still reports the 28dB downstream Attenuation that it did on ADSL1, but my Billion 7800N now shows 31dB.
I realize routers vary in their reported figures, but I have one that has hung onto the same attenuation.