Recommend ADSL chipsets for low ish SNR lines

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omfg

5 posts

Wannabe Geek

#114752 1-Mar-2013 17:40

I've been a long time periodic lurker on these forums, although I live in AU these days.

Before I left, I set up my in-laws with a Billion 5100 on a semi-rural line. They use TelstraClear - although I'm unsure whether they are ULL or wholesale.

The router's log shows a typical sync as:

01/01/1970 00:00:17> Modulation: G.dmt
01/01/1970 00:00:17> Annex Mode: ANNEX_A
01/01/1970 00:00:17> Max Tx Power: -38dBm/Hz
01/01/1970 00:00:17> CO Vendor: N/A
01/01/1970 00:00:17> d/s SNR: 12.4dB, u/s SNR: 15.0dB
01/01/1970 00:00:17> d/s Attenuation: 39.8dB, u/s Attenuation: 19.0dB
01/01/1970 00:00:17> d/s Data Rate: 5984kbps, u/s Data Rate: 896kbps

Nothing too special.

Now, as this router is almost 10 years old, I was planning to replace it when I come back to visit shortly, both to get them a better sync and to prevent uPNP weirdness that likes a reboot every couple of weeks.

All the talk on Whirlpool seems to lean towards matching ADSL chipsets with the ports used at the Telco, as well as some chipsets working better on poor SNR lines, and others working better over short distances etc.

Has anyone got any advice on chipsets in NZ, especially regarding specific chipsets that you've found to work well on lower-quality/long run lines?

Ragnor

8192 posts

Uber Geek

Trusted

#773672 2-Mar-2013 17:33

It's most likely Chorus DSL equipment with Broadcom line card if it's rural. Chorus use Ikanos line cards in new deployments.

Broadcom chipset works great on either.

Can't remember what vendor Telstraclear were using for their LLU, doesn't look like a LLU connection though as it wouldn't be G.dmt/ADSL1 and most LLU uses more aggressive noise margin than Chorus does (eg: 9dB or 6dB instead of 12 dB).

Check the address in http://chorus.co.nz/sat to see what exchange/cabinet they are connected to and whether ADSL2+ is available.

Also might as well install a master filter/splitter while you are there to isolate the DSL line from the undoubtedly daisy chained internal phone wiring. Could be getting more line rate even on ADSL1 (G.dmt) with 40dB attenuation.

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omfg

5 posts

Wannabe Geek

#773864 3-Mar-2013 13:09

Awesome reply, thanks.

From what you're saying, Broadcom seems to be the way to go. I've checked their address in the tool and they're well outside any ADSL2+ coverage. This leads me to agree that they are more than likely on a (Broadcom) Chorus DSL port.

I've got a TG585v7 based on a BCM6338 which I can give them or I can pick up a TD-W8950N (unknown BCM chipset) fairly cheaply too.

I've not done a master splitter install before, and I probably don't want to start now. I could look in to getting an installer to come out though, assuming they're still $150-200.

What do you estimate would be achievable goal on a G.Dmt line at 40dB attenuation?

cyril7

9050 posts

Uber Geek

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Trusted

Subscriber

#773883 3-Mar-2013 14:06

Hi, at 40dB expect around 4-6Mb/s, about 4yrs back in Waikanae I was sitting on 43dB and with a master filter and correct wiring sat on 4.6-5Mb/s. That said YMMV depending on how many other DSL services are in the feeder your on and what size that feeder is.

Cheers
Cyril