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Standard User R0NSKI
(experienced) Fri 26-Apr-13 10:29:37
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Re: BTOR Flat modem cable


[re: underzone] [link to this post]
 
Considering he is a very helpful and experienced BT engineer / technician I doubt it very much.

Standard User StephenTodd
(committed) Fri 26-Apr-13 15:44:13
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Re: BTOR Flat modem cable


[re: R0NSKI] [link to this post]
 
Some pretty bad results from my replacement of the original with the ebay cable I mentioned above.
Small increase in Max downstream rate, small decrease in max upstream rate.
Significant decrease in actual downstream rate, probably because I changed cable when the snr was a little low.

The really bad bit is that my downstream RSCorr rate has gone from around 60 per second to over 200 per second.

~~~


Taken just before the switch
Text
1
23
45
67
89
1011
1213
C:\utils>modem
Microsoft (R) Windows Script Host Version 5.8Copyright (C) Microsoft Corporation. All rights reserved.
 Max:    Upstream rate = 23552 Kbps, Downstream rate = 83056 Kbps
Path:   0, Upstream rate = 20000 Kbps, Downstream rate = 76179 Kbps                Down            Up
SNR (dB):        4.4             12.7D:              1207            1               (interleave)
delay:          8.00            0.00               (interleave)ping bbc ...
  Sent = 25, Received = 25, Lost = 0 (0% loss),  Minimum = 29.21ms, Maxiumum = 32.44ms, Average = 30.45ms

Taken just after the switch
Text
1
23
45
67
89
1011
1213
C:\utils>modem
Microsoft (R) Windows Script Host Version 5.8Copyright (C) Microsoft Corporation. All rights reserved.
 Max:    Upstream rate = 22182 Kbps, Downstream rate = 83336 Kbps
Path:   0, Upstream rate = 20000 Kbps, Downstream rate = 70273 Kbps                Down            Up
SNR (dB):        6.4             7.0D:              1113            1               (interleave)
delay:          8.00            0.00               (interleave)ping bbc ...
  Sent = 25, Received = 25, Lost = 0 (0% loss),  Minimum = 25.67ms, Maxiumum = 38.07ms, Average = 26.64ms


--
Moved (with trepidation turned relief) to BT Infinity 2 for upload speed. Happy BE user for several years.
Standard User MHC
(sensei) Fri 26-Apr-13 15:51:50
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Re: BTOR Flat modem cable


[re: StephenTodd] [link to this post]
 
The max upstream decrease as well as losing 5dB margin is a little odd.

Can you make out which wire is connected to which pin at each end?


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C


taurus excreta cerebrum vincit


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Standard User Going_Digital
(knowledge is power) Fri 26-Apr-13 16:05:50
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Re: BTOR Flat modem cable


[re: StephenTodd] [link to this post]
 
It is worth pointing out that there are lots of cables around that are not wired correctly. They need to be wired so that the centre two pins are wired on a single pair, but many are wired so that they are two pairs side-by-side resulting in the signal going down 2 halves of a pair, making the results as bad if not worse than the flat cable.

adslnation - A Tandy Brand.
http://www.adslnation.com
Standard User StephenTodd
(committed) Fri 26-Apr-13 17:14:39
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Re: BTOR Flat modem cable


[re: Going_Digital] [link to this post]
 
It is wired 1-1, 2-2, 3-3, 4-4.

Centre pair with orange and orange/white.
Outer pair with green and green/white

That sounds as if it is correct from what you say?
Maybe it would be better for the outside not to be wired at all, or ...?

--
Moved (with trepidation turned relief) to BT Infinity 2 for upload speed. Happy BE user for several years.
Standard User Going_Digital
(knowledge is power) Fri 26-Apr-13 20:47:25
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Re: BTOR Flat modem cable


[re: StephenTodd] [link to this post]
 
Sounds like it is wired correctly then, suppose it could be a poor quality CCA (Copper Coated Aluminium) cable that might explain the difference. At the price they are charging with free delivery it is unlikely to be just copper as the price of coper is expensive at about US$7000 per ton.

adslnation - A Tandy Brand.
http://www.adslnation.com

Edited by Going_Digital (Fri 26-Apr-13 20:48:00)

Standard User StephenTodd
(committed) Fri 26-Apr-13 21:24:15
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Re: BTOR Flat modem cable


[re: Going_Digital] [link to this post]
 
Yes, thanks for the comment. I've just got to assume it is rubbish cable.

I reinstalled it again temporarily, being very careful it was well separated from any other cables etc; and errors shot up again.
I might take it apart and have a look ~ it's valueless to me and probably to anyone else in its current form.
I just hope the several modem disconnects don't give DLM silly ideas.

--
Moved (with trepidation turned relief) to BT Infinity 2 for upload speed. Happy BE user for several years.

Edited by StephenTodd (Fri 26-Apr-13 21:24:48)

Standard User StephenTodd
(committed) Sat 27-Apr-13 15:09:00
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Re: BTOR Flat modem cable


[re: StephenTodd] [link to this post]
 
I've reinstalled my original Openreach supplied flat cable and been more careful to route it away from everything else. (The various cables look even more of a mess now.)
The downstream max rate hasn't changed significantly (hovering around 83000),
and the downstream path rate is still the lower value (70258 against 76179 before fiddling) (? DLM lowered rate after short bad periods with the other cable?).

However, my downstream RSCorr rate seems to have dropped very significantly.
Was around 60 per second before fiddling, went up to 200 per second with the bad cable, and now showing an average of 8.5 per second after 17 hours.
I don't know how much that is to do with the slower speed from a more conservative 6.5 snr against around 4.5 before

Too soon to be confident of anything but ....
It'll be interesting to see if DLM sees the lower error rate and takes off at least some of my 8ms interleaving (D: 1113).
Maybe cable routing, even for a 2m cable, is more significant than I thought.

--
Moved (with trepidation turned relief) to BT Infinity 2 for upload speed. Happy BE user for several years.
Standard User mikehiow
(committed) Sat 27-Apr-13 18:10:42
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Re: BTOR Flat modem cable


[re: StephenTodd] [link to this post]
 
Send me a SAE big enough and I'll happily make you a cable to try...

ZeN > plusnet > entanet > <aaisp.net> > Sky LLU > WightWireless > Plusnet FTTC 73/17
Standard User StephenTodd
(committed) Sun 28-Apr-13 14:54:09
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Re: BTOR Flat modem cable


[re: mikehiow] [link to this post]
 
Thanks for that very kind offer. I'd like to take you up on it if you can PM me your address, please?

I'm away for a bit towards the end of the week so may not have a chance to try it for a week or two.
Also just ordered an HG622 (now all gone, from the other active thread http://forums.thinkbroadband.com/fibre/f/4233951-hua... ). I'll try to keep experiments with that apart from experiments with the cable.

--
Moved (with trepidation turned relief) to BT Infinity 2 for upload speed. Happy BE user for several years.
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