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I'm in need of some current info regarding BTWS policy on long lines and OOL ADSL. Specifically what the distance limitations are and what BTWS responsibilities are regarding getting ADSL's working. Are there any relevant SIN's that I could read? This is pertaining to fixed speed datastream products. Thanks.
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http://www.farina1.com/bookmark/000004/2005/02/27/00020260.HTM
2Mbps, under 43dB attenuation
1Mbps, under 60dB attenuation
0.5Mbps, BT Wholesale has no specific limit, it will try the line no matter what length
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In reply to:
2Mbps, under 43dB attenuation
1Mbps, under 60dB attenuation
No longer true...the ISP can order what it likes..IF however an Openreach CSE says the line can't handle it.....
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They are still the BT wholesale limits for fixed rate services
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But being happily ignored by just about everyone these days !
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Except the NHS 
All of our 16,000 odd ADSL's are fixed rate datastream.
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If your two meg line is on a 47db attenuation line, as long as the snr is acceptable, it won't be knocked back......
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Well I may as well post what happened with this specific site. It was a half meg service that was syncing with 63.5 db attenuation and 10.5 db noise margin, and massive CRC and header errors, so very slow. The upstream wasn't much better (40 db / 17 db) @ 256k at lots of errors (a lot less than the downstream though).
So it went to BTWS and strangely the ADSL upstream suddenly re-synced at 192k with a reduced error count and the noise margin on the downstream jumped up to 13 db. They then sent out a SFI guy and the ADSL magically re-synced at 256k and the noise margin on the downstream again went up to 14 db. and the errors reduced massively. Then they decided to come back with no fault found and declare that they would be charging us! Wonderful stuff and as usual an exemplary performance by BTWS.
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In reply to:
Then they decided to come back with no fault found and declare that they would be charging us!
Clear codes have changed recently, which one was used in this case, it could be BTw misreading the result. (By the way, that's a seriously long line, the 63.5 is the software glitch allowing it to show no more, but judging by the 40db u/s...it's long)
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In reply to:
(By the way, that's a seriously long line, the 63.5 is the software glitch allowing it to show no more, but judging by the 40db u/s...it's long)
Heh, you're completely right. I'd forgotten about that glitch. The line isn't actually that long, around 5.6km if my memory serves, I'll check tomorrow. It's just a [censored] line, probably got some aluminum in there. I'll check the clear code as well for you.
You're not wrong about BTW using the wrong clear codes. They tried to claim a 512k ADSL on a 1.13km line was OOL :S Then they realised they'd used the wrong code.
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Line is 5.61km. Here are the current stats as reported by the router:
Noise Margin: 14.0 dB 16.0 dB
Output Power: 17.5 dBm 12.0 dBm
Attenuation: 63.0 dB 31.5 dB
That's down then upstream.
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OK, so 14db snr is good enough on a 512 long line.....that'd get an FNF from me (based on that alone anyways  )
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Yeh it's 14db now, after a couple of CSE visits. It was 10.5db. I always joke with NTL that BTWS need to replace their keyboards that "limited layout" (the keyb's with FNF, NFF, RWT buttons) and actually replace them with keyb's that allow their testers to write something meaningful. Then again that might be hoping for too much,
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Trust me, we put the data on the job notes, it seems that no one takes any notice, or relates this to anyone else.
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