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Standard User nemeth782
(member) Tue 02-Feb-16 08:13:06
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Awful line stats


[link to this post]
 
At work, I have the great pleasure of sharing a pathetic BT DSL line.

It used to be awfully slow, but you could browse the internet, with a sync of around 1.5mbit.

These are the current stats, it's been this way a week or two now...


Modem Type: Built in modem - ADSL
DSL Line (Wire Pair): Line 1 (inner pair)
Current DSL Connection:
Down Up
Rate: 480 kbs 448 kbs
Max Rate: 440 kbs 644 kbs
Noise Margin: 6.0 dB 12.0 dB
Attenuation: 63.0 dB 31.5 dB
Output Power: 15.5 dBm 12.4 dBm

Protocol: G.DMT Annex A
Channel: Interleaved
DSLAM Vendor Information Country: {46336} Vendor: {IFTN} Specific: {51313 }
ATM PVC: 0/38

Rate Cap: 440 kbs
Attenuation @ 300kHz: 63.0 dB
Uncanceled Echo: -19.5 dB Ok
VCXO Frequency Offset: -61.4 ppm Ok
Final Receive Gain: 29.9 dB Ok
Excessive Impulse Noise: 0 Ok


I'd expect more like 2mbit for 63dB attenuation.

BT seem to be incapable of doing anything about it.

Any ideas? It's taken about 5 minutes for the page to load to post this frown
Standard User ian007jen
(committed) Tue 02-Feb-16 09:32:35
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Re: Awful line


[re: nemeth782] [link to this post]
 
Hi,

Your Upstream noise margin has been increased from 6 dB to 12 dB this has reduced your download synch to what it is currently,

Dial 17070 (then option 2) on a wired phone plugged into the test socket and listen for crackles static etc.

If you do hear anything report to your phone line provider as a fault.
Standard User RobertoS
(elder) Tue 02-Feb-16 10:07:38
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Re: Awful line stats


[re: nemeth782] [link to this post]
 
Your attenuation could be higher than 63dB. That, and 31.5dB upstream are simply the maximum most routers display.

As per the previous poster for what to check first. That's assuming you gave already power-cycled the router. Once the speed drops like that it rarely re-sync's faster automatically.

The indispensable man or woman passes from the scene, and what happens next is more or less the same thing as was happening before.
My broadband basic info/help site - www.robertos.me.uk. Domains, site and mail hosting - Tsohost.
Connection - AAISP Home::1 80/20. Sync 59504/15641kbps @ 600m. - BQM


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Standard User sthen
(committed) Wed 03-Feb-16 10:13:06
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Re: Awful line


[re: ian007jen] [link to this post]
 
In reply to a post by ian007jen:
Hi,

Your Upstream noise margin has been increased from 6 dB to 12 dB this has reduced your download synch to what it is currently,

Dial 17070 (then option 2) on a wired phone plugged into the test socket and listen for crackles static etc.

If you do hear anything report to your phone line provider as a fault.


Also try at least a different filter, and ideally also router. And if you haven't already tried the router directly in the master socket and physically disconnecting any extension cabling etc, do that too - with a line like that, any improvement you can make is going to be useful.
Standard User eckiedoo
(experienced) Wed 03-Feb-16 10:56:09
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Re: Awful line stats


[re: nemeth782] [link to this post]
 
As well as the other tests, as you are in a "work" situation, check the internal wiring, particularly any plugs and sockets.

Pull out and Insert any plugs and sockets a few times, to help clean of any corrosion, dendrites etc that may have built up over the years.

Also subject to the exact arrangements, make sure that there are xDSL Splitters (marked normally PHONE - MODEM or suitable icons) at each working conventional Phone plugged in.

(I have encountered a simple phone socket doubler being used instead of an xDSL Splitter, as superficially, they can be virtually identical in appearance!)

If any of the wiring makes use of screw connections, slacken them of slightly, spray with a suitable lubricant, then tighten. Ensure that the lubricant does not stray on to any "working electronics.
Standard User Zarjaz
(eat-sleep-adslguide) Wed 03-Feb-16 15:13:04
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Re: Awful line stats


[re: eckiedoo] [link to this post]
 
'Dendrites' are you sure about that ??

"dendrite

plural noun: dendrites
1.
PHYSIOLOGY
a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body.
2.
a crystal or crystalline mass with a branching, tree-like structure."

Standard User eckiedoo
(experienced) Wed 03-Feb-16 16:50:00
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Re: Awful line stats


[re: Zarjaz] [link to this post]
 
Yes.

It also covers the crystalline, non-conducting growths that can occur between mating parts of contacts, particularly gold-plating and cadmium-plating, if a fairly consistent DC current is present.

Thus covered by-
"
2.
a crystal or crystalline mass with a branching, tree-like structure."


Crystals are generally non-conducting, as exemplified by water.

Pouring very hot water on an Earth Rod in solidly-frozen ground, cured our PBX problems on several occasions - almost Standard Procedure.

----------

Also often cured by giving equipment a good thump!

Knowing the exact physics and location of such thumps was a fine art.

----------

I suspect not encountered so often nowadays, as generally there are fewer such contacts actually within equipment; and any plating is likely to be passivated - but was quite frequently encountered in earlier days.

Certainly it was often recommended that such connections were opened and closed a few times, particularly during maintenance and fault-finding.

Often compounded by hygroscopic effects as well, causing rather similar corrosion growths, by water vapour being trapped within the connecting area.

Thus also a reason for the gels that have been incorporated in to so many telephone connectors, exemplified by "gel crimps".
Standard User eckiedoo
(experienced) Thu 04-Feb-16 11:27:10
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Re: Awful line stats


[re: Zarjaz] [link to this post]
 
Morning Zarjaz and others

A fuller explanation-

https://en.wikipedia.org/wiki/Whisker_(metallurgy)

Worth being aware o; and many may have encountered the situation, without realising the causes.

Interesting the mention of "compression" which in various ways, occurs in plugs and sockets.
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