I was trying to diagnose problems with a newly-activated broadband line for
a customer yesterday. Can I check that I've made the correct deductions
about where the problem lies?

BT Voyager 220 router (1 ethernet, 1 USB, no wireless)

Router in master test socket (extension wiring disconnected) works fine:

2.5-3 Mbps downstream
6 dB margin
63 dB attenuation


Router in other sockets (either the faceplate of the master socket or a
hard-wired extension from the back of the master socket) - sometimes works
fine but sometimes fails to sync. Remains in one state for a hour or so - it
consistently works or consistently fails. When it works I get

1 Mbps downstream
5.3 dB margin
63 dB attenuation


Given that attenuation is the same but the speed is much less (or the router
fails to sync at all), it looks as if it's the house wiring that's picking
up some noise that is causing the router to negotiate a lower speed in order
to achieve roughly the same noise margin.

I tested with the router in the front of the master socket and nothing in
any of the extension sockets, then gradually plugged in filtered phones, but
the statistics didn't change - so it looks like wiring rather than duff
equipment plugged into the wiring.

What sort of things could cause interference to ADSL such that it
consistently fails for an hour or so or else consistently works for an hour
or so. As far as we could establish, no electrical equipment was being used
during the dead time that wasn't also being used when the router could sync.

Who are the best people to investigate house wiring problems? Without the
right tools for re-crimping wires, I'm reluctant to start pulling out wires
from the back of the faceplate myself, especially as there is very little
spare wire - there's hardly room to swing a cat when I undo the faceplate.

Remove any unused but terminated cables. Replace the wiring , go from socket
to socket and ensure all daisy changed sockets have good connections


There is info on the DSL Zone site to help you with wiring


Cub

"Mortimer" <me@privacy.net> wrote in message
news:13gp4m0bqe34kc6@corp.supernews.com...

Mortimer wrote:

You're doing well there with 63dB of attenuation !


It's almost certainly the imbalance caused by the ring circuit degrading the
ADSL signal actually. Been there done it myself.

Since the extension wiring isn't BT's, just remove the ring circuit. Most
(effectively all) phones don't need it any more anyway and a microfilter (which
you ARE using on the extensions aren't you ?) regenerates the ring signal
anyway.

Graham

On 10-Oct-2007, Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote:

Ideally use one ADSL filter to feed all the phones.
A premium quality one stabilised my line, plugged it into
the NTE faceplate, the ADSL modem into its RJ11, and
plugged the existing cheapo filter into the BT jack on
the quality filter, and the phones into that.
Effectively putting two phone filters in series.
Phones, extra ringer, CLID unit, and voice quality,
all ok, with stable BB speed.

Long high attenuation lines are problematical,
the weak received HF signals for your BB can suffer
crosstalk from neighbouring BB pairs, same
applies to the exchange end, your signal is weak
and competing against neighbouring BB pairs.
It's called NEXT (Near End Cross Talk) and
quality cables have a lower NEXT figure.
So line noise can vary considerably over time and
if sync is lost it may take time to re-establish
itself.
All you can do is use a modem that works
well with long high attenuation lines, then fit
the best filter(s) you can find, whilst
simplifying the extension phone wiring as
much as possible. Too much stuff on
the phone side is detremental. Unhooking
a solenoid trembler extension ringer helped a lot.

Eeyore wrote:
necessary if you remove the third wire.They are often a false economy
(he says from experience). Worth paying the £10 for proper ones from
Maplin or similar.

Is the house wiring proper paired cable (blue and blue/white pairs etc)
or is it old Blue/green/Brown/Orange stuff?
Or even worse alarm cable.

Neither of these are proper 'twisted pairs' and can severely upset things.

As others have posted, the filtered faceplate on the master socket cures
most ills. If you need to extend to a modem a bit further away, it is
often better to still install the faceplate and then purchase a long
RJ11/RJ11 cable for the ADSL data (As always however don't be conned
into PC W****'s highly expensive versions

Mike

Mike J wrote:

The cheap ones I've seen do absolutely have the ring capacitor, but inany event
you'll be hard pressed to find aphone that hasn't already got its own !


Nonsense.
http://www.maplin.co.uk/Module.aspx?...LTER&doy=10m10

IS a 'cheap' filter. Can be had for £2 or less on ebay.

http://cgi.ebay.co.uk/3x-BT-ADSL-Bro...QQcmdZViewItem

is basically the same thing.

Graham

"Mortimer" <me@privacy.net> wrote in message
news:13gp4m0bqe34kc6@corp.supernews.com...
My line has 60db attenuation. The only way I can get a stable ADSL
connection is to use a router connected to my master socket, and to connect
my household phone wiring via a microfilter. (One day I may get a fancy
filtered face plate.) This arrangement is not uncommon for people with high
loss lines.

Prior to this arrangement my line was most likely to fail at about 9pm
which is the time when most people are using ADSL.


--
Michael Chare

Eeyore wrote:

The cheap ones from CPC definitely don't have the capacitor!!

Mike

Mike J wrote:

That really is scraping the bottom of the barrel for cheapnes, but as I explained is unlikely to ever cause a problem.

Graham

Mike J wrote:
This topic was discussed ad nauseum some months ago. Graham just can't seem
to grasp the fact the the more expensive designs provide a better solution.
As well as providing better filtration the design does not degrade the ADSL
side of things as the cheap models can sometimes do. On a high loss line it
can make the difference between ADSL working or not. On a better line there
is likely to be little difference in most, but not all, cases.


Peter Crosland

g6jns@yahoo.co.uk

On 10-Oct-2007, "Michael Chare" <MunderscoreNEWS@chareDOTorg.uk> wrote:

Probably due to crosstalk, pushing many simultaneous ADSL carriers
through adjacent pairs would be expected to raise the noise level and
lower the SNR.

Peter Crosland wrote:

And you believe that spending lots of money for no good reason (mainly on marketing puff) is an intelligent idea.

Graham

Peter Crosland wrote:

The same kind of story is told about hi-fi cables costing thousands of pounds. It's a quasi-religious belief.

Show me some science that supports either idea and I'll take note of it.

Graham

Mortimer wrote:
and now run adsl and a dect phone off a single master socket.

I really don't see why people need a lot of internal extension wiring
now we have wireless phones.

However I must admit I do have my house wired with a LAN but I think
even the LANs days are numbered.

On Thu, 11 Oct 2007 09:48:42 UTC, Nick <nospam@spam.com> wrote:

Some houses have thick walls.
It's possibly more secure.
It works better if the house has a PBX (like mine!)

Some houses have thick walls.
It may be more secure.
It's still cheaper.
It's potentially faster.
--
[ 7'ism - a condition by which the sufferer experiences an inability
to give concise answers, express reasoned argument or opinion.
Usually accompanied by silly noises and gestures - incurable, early
euthanasia recommended. ]

Bob Eager wrote:

Show me a wireless gigabit LAN !

Graham

Eeyore wrote:
My current highest transfer rate is ~70 Mbs, copying hard drive files. I
wonder what do you need a domestic gigabit LAN for.

Nick wrote:

If it exists, some people at least will want it.

Graham

Bob Eager wrote:
Obviously some houses have thick walls but is it a problem in a
significant proportion of houses?


I couldn't get 802.11g to work in my house (because I have the phone
socket in the study which has a cavity wall (at an angle) between it and
the rest of the house). However The 802.11g routers look much better. If
I get a laptop I'll sort out a wirelss lan.

On Thu, 11 Oct 2007 10:21:06 UTC, Nick <nospam@spam.com> wrote:

Copying lots of files faster of course!
--
[ 7'ism - a condition by which the sufferer experiences an inability
to give concise answers, express reasoned argument or opinion.
Usually accompanied by silly noises and gestures - incurable, early
euthanasia recommended. ]