Billion 7700N

I've just taken delivery of a 7700N and I think there is something a bit strange going on. Before I start "fiddling" can anyone confirm that this is not right.

I have an ADSL2+ line. In the routers config (Advanced Setup / DSL) I have check marks against the following (the default settings)...

G.Dmt Enabled
ADSL2 Enabled
ADSL2+ Enabled
AnnexM Enabled

I assumed that these will be tried in reverse order, if it can't connect using ADSL2+ AnnexM it will try ADSL2+, and so on.

However, looking at the connection status (Device Info / Statistics / xDSL) I see that the mode is shown as ADSL_G.dmt; the manual indicates that I should see ADSL2+ (or maybe ADSL2plus) there. Some other stats, specifically line speed and attenuation, also seem to indicate that I am in normal ADSL mode.

I note that the manual also states "The router may require firmware modifications for certain ADSL2 / 2+ / Annex M DSLAMs". Anyone know anything about that?

The first step will be to disable G.Dmt and ADSL2, to see if that forces an ADSL2+ connection, but before I try, and risk the wrath of BT's DLM, I thought it worth asking here.

Ian

The router should connect in ADSL2+ mode with the default settings, if it doesn't try these settings which i have on my Billion 7800N (interface should be similar):
http://tinypic.com/r/16kak1u/7

Can i ask where you got the router from?

Thanks, I'll try those settings first. The layout is different, but the same fields are present.

I got it from BroadbandBuyer; £46.76 inc VAT

Ian

Those changes (Annex L on, G.Dmt off) made the difference. It now shows ADSL2plus and the downstream attenuation has increased by 4dB as expected.

Thanks

Can I ask how well it connects compared to your other ADSL modems? Sync speed wise / stability?

Thanks!

-- gyre --

It's a bit difficult to tell really. My main reason for changing router, I previously had a BT2700HGV, was to get one which could adjust the default SNR; because of a faulty low-energy light bulb BT's DLM had set mine to 9dB (from a very stable 3dB) and showed no inclination to drop it down again.

I've only had the 7700N for a couple of days and it seems stable. I've tweaked the SNR setting to default to 3dB, it drops to between 1 and 2dB at night, and I haven't seen any _unexpected_ re-syncs. The DLM is still generating a resync every 2 days though <sigh>.

Speed wise it seems slower than the 2700HGV. At 3dB that would give me 8500-9500 ish. The best I've seen so far from the 7700N is 7500 ish. I'm going to reduce the SNR adjustment again tomorrow so that might bring the speed up a bit more?

Other than that it seems quite a nice router. The wireless connection, using 2g, seems faster than the 2700HGV and it's nice to have a Telnet interface again.

Ian

Thanks for the info. I also have something similar... a 2700HG (no V). I'm on 9dB target snr. It's very stable, but I also miss the ability to tweak

I've ordered a 7700N myself today... will see how I get on. Hopefully it will run in just dumb modem mode connected to my draytek 2920.

-- gyre --

Received mine today from Broadbandbuyer.

Am using it in bridged mode on a very long line. So far I'm impressed with how well it is holding on.

Was oddly easy to set it into bridged mode. I was expecting it to be a real chore, as the advanced settings aren't for the faint of heart

-- gyre --

In reply to a post by gyre:

Received mine today from Broadbandbuyer.

Am using it in bridged mode on a very long line. So far I'm impressed with how well it is holding on.

Was oddly easy to set it into bridged mode. I was expecting it to be a real chore, as the advanced settings aren't for the faint of heart

-- gyre --

Interesting - thanks.Wondering if it would improve my sync rate.

How long is your line BTW -mine is 6.2km with an attenuation of 63 - around 82 @ 300KHz.

Barrie

I don't exactly know how long my line is. Before BT added extra checks to the 17070 number, they claimed it was about 4.7km. But lots of things have changed in the last few years, as I've been lifted and shifted at least twice.

My attenuation is shown at 63.5 using g.dmt. But then, I believe that it isn't specified to show anything larger. I force the system to use g.dmt as opposed to adsl 2+, as it gives a higher sync and appears more stable for me.

-- gyre --