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uk.telecom.broadband (UK broadband) (uk.telecom.broadband) Discussion of broadband services, technology and equipment as provided in the UK. Discussions of specific services based on ADSL, cable modems or other broadband technology are also on-topic. Advertising is not allowed.

What sort of fault might this be?



 
 
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  #1  
Old September 29th 08, 10:23 AM posted to uk.telecom.broadband
Gordon Henderson
external usenet poster
 
Posts: 797
Default What sort of fault might this be?

Heres one that's new to me )-:

Elminated all internal wiring by plugging directly into master socket. I
have tried 3 different microfilters and 2 differnet modem/routers, but
the result is the same :-

With the modem/router turned off, the phone line is clear, but as soon as
I turn the router on and it starts to sync the line starts to sound hissy
with the occasional crackle. This i swith nothing more than a microfilter
plugged into the test port, a standard analogue phone and Draytek router
(one of 2 I've tried - a 2600+ and a 2600vg)

Broadband is mostly the full 8Mb, although I'm only 0.5Km from the
exchange, SNR isn't really what I'd expect. Currently seeing:

up: 736000 down: 6880000 snr: 15.5 loopAtt:23.0

So I know that if I call BT they'll just tell me it's my equipment,
(as in, oh listen, it's silent when you turn off the router so it must
be the router) and charge me for a call-out fee, so is there anything
that anyone in the past has seen that would cause this? Something I
could tell the BT teletubby that they might belive?

This has happened before - during a period of bad weather, but it's been
nice here for weeks now!

If anyone has any clues, magic words to say to BT, etc. I'd appreciate it.

Thanks,

Gordon
  #2  
Old September 29th 08, 10:32 AM posted to uk.telecom.broadband
Peter Crosland
external usenet poster
 
Posts: 1,463
Default What sort of fault might this be?

Heres one that's new to me )-:

Elminated all internal wiring by plugging directly into master socket. I
have tried 3 different microfilters and 2 differnet modem/routers, but
the result is the same :-

With the modem/router turned off, the phone line is clear, but as soon as
I turn the router on and it starts to sync the line starts to sound hissy
with the occasional crackle. This i swith nothing more than a microfilter
plugged into the test port, a standard analogue phone and Draytek router
(one of 2 I've tried - a 2600+ and a 2600vg)

Broadband is mostly the full 8Mb, although I'm only 0.5Km from the
exchange, SNR isn't really what I'd expect. Currently seeing:

up: 736000 down: 6880000 snr: 15.5 loopAtt:23.0

So I know that if I call BT they'll just tell me it's my equipment,
(as in, oh listen, it's silent when you turn off the router so it must
be the router) and charge me for a call-out fee, so is there anything
that anyone in the past has seen that would cause this? Something I
could tell the BT teletubby that they might belive?

This has happened before - during a period of bad weather, but it's been
nice here for weeks now!

If anyone has any clues, magic words to say to BT, etc. I'd appreciate it.



At the risk of stating the obvious have you tried just the filter and router
plugged into the test socket with nothing else connected? It does appear
likely that the problem is not with BT so don't involve them. The other
possibility is that both router and/or filters have faults. Can you borrow
another of both to try? Are the filter good quality branded ones rather than
the anonymous T shaped variety?

Peter Crosland


  #3  
Old September 29th 08, 10:44 AM posted to uk.telecom.broadband
Gordon Henderson
external usenet poster
 
Posts: 797
Default What sort of fault might this be?

In article ,
Peter Crosland wrote:
Heres one that's new to me )-:

Elminated all internal wiring by plugging directly into master socket. I
have tried 3 different microfilters and 2 differnet modem/routers, but
the result is the same :-

With the modem/router turned off, the phone line is clear, but as soon as
I turn the router on and it starts to sync the line starts to sound hissy
with the occasional crackle. This i swith nothing more than a microfilter
plugged into the test port, a standard analogue phone and Draytek router
(one of 2 I've tried - a 2600+ and a 2600vg)

Broadband is mostly the full 8Mb, although I'm only 0.5Km from the
exchange, SNR isn't really what I'd expect. Currently seeing:

up: 736000 down: 6880000 snr: 15.5 loopAtt:23.0

So I know that if I call BT they'll just tell me it's my equipment,
(as in, oh listen, it's silent when you turn off the router so it must
be the router) and charge me for a call-out fee, so is there anything
that anyone in the past has seen that would cause this? Something I
could tell the BT teletubby that they might belive?

This has happened before - during a period of bad weather, but it's been
nice here for weeks now!

If anyone has any clues, magic words to say to BT, etc. I'd appreciate it.



At the risk of stating the obvious have you tried just the filter and router
plugged into the test socket with nothing else connected? It does appear
likely that the problem is not with BT so don't involve them. The other
possibility is that both router and/or filters have faults. Can you borrow
another of both to try? Are the filter good quality branded ones rather than
the anonymous T shaped variety?


Yes, I have tried both routers directly into the socket - they sync OK, but
not at the values I'd expect. (Same SNR/LoopAtt values)

And while there is a possibility the router have faults, I doubt it -
I've been using them since I got ADSL. I have graphs of the SNR/LoopAtt
values too for the past year, so I know it's never been right for a long
time (considering my distance from the exchange and based on neighbours
connections) - it's only recently it's started to get worse...

Actually, I've tried 4 microfilters - the "normal" one I use is a box
mounted faceplate from solwise - at the end of 5m of cat5 cable from
the master socket - that yields the same results, so I went right back
to the master socket for the rest of my tests.

I'm fairly sure I did ready about someone recently with a similar fault,
but I've done a search here and elsewhere, but not come up with anything
yet - corroded wire, high resistance, bad connection, *something* like
that in the external BT cabling, but ...

Gordon

  #4  
Old September 29th 08, 11:24 AM posted to uk.telecom.broadband
John Weston
external usenet poster
 
Posts: 108
Default What sort of fault might this be?

In article ,
says...


Yes, I have tried both routers directly into the socket - they sync OK, but
not at the values I'd expect. (Same SNR/LoopAtt values)

And while there is a possibility the router have faults, I doubt it -
I've been using them since I got ADSL. I have graphs of the SNR/LoopAtt
values too for the past year, so I know it's never been right for a long
time (considering my distance from the exchange and based on neighbours
connections) - it's only recently it's started to get worse...

Actually, I've tried 4 microfilters - the "normal" one I use is a box
mounted faceplate from solwise - at the end of 5m of cat5 cable from
the master socket - that yields the same results, so I went right back


Do you have any home phone wiring? If so, this will probably be
connected to the back of the master faceplate so your wiring described
above, if I understand it correctly, is wrong. The filter MUST be
connected between the incoming phone wires and all your home phone-type
equipment and wiring. It must be connected before any home phone
wiring, for best effect. What it appears you have done is to connect a
filter into a "box mounted faceplate from Solwise at the end of 5m of
cat5 cable from the master socket". How does this filter remove the
ADSL signal from your home phone wiring?

Don't forget that an ADSL filter does nothing between the phone line
and the ADSL modem. It only provides a low-pass filter, to remove the
ADSL part of the combined signal, between the incoming phone line and
the internal telephony wires and devices. Your description of the
problem (the ADSL HF noise) sounds like you don't have a filter between
the incoming phone line and your telephone.

That said, your test putting the filter into the test socket and
plugging the telephone into the filter's phone socket (you did this,
didn't you?), with the modem in the filter's ADSL socket, should have
removed the ADSL signal from the phone. You are close to the exchange,
so I'd try putting more than one filter in series with the telephones.
This is because filters aren't sharp cut-off devices so the lower
frequency ADSL signals may still be audible (I used to work with a
"golden ears" who could hear cross-talk at -60dB) You can get filters
with sharper cut-off characteristics that perform better on short lines
than the standard design.

Also, try disconnecting the pin-3 ring wire. It may be picking up the
ADSL signal and coupling it into the phone side of the wiring (but not
likely if you did the test socket connection correctly...)

ADSL filters do fail. They have capacitors in them which can change
characteristics with age (and high ring signals). Try a new faceplate
filter. I've had good performance with ADSLnation ones - but they also
will age...
--
John W
Replace the obvious with co.uk twice to mail me
  #5  
Old September 29th 08, 11:52 AM posted to uk.telecom.broadband
Gordon Henderson
external usenet poster
 
Posts: 797
Default What sort of fault might this be?

In article ,
John Weston wrote:
In article ,
says...


Yes, I have tried both routers directly into the socket - they sync OK, but
not at the values I'd expect. (Same SNR/LoopAtt values)

And while there is a possibility the router have faults, I doubt it -
I've been using them since I got ADSL. I have graphs of the SNR/LoopAtt
values too for the past year, so I know it's never been right for a long
time (considering my distance from the exchange and based on neighbours
connections) - it's only recently it's started to get worse...

Actually, I've tried 4 microfilters - the "normal" one I use is a box
mounted faceplate from solwise - at the end of 5m of cat5 cable from
the master socket - that yields the same results, so I went right back


Do you have any home phone wiring?


No.

Actually yes, but I did say I was plugged directly into the master socket
which disables all internal wiring. I may not have been quite clear, but
I really meant the test socket on the BT fitted box.

If so, this will probably be
connected to the back of the master faceplate so your wiring described
above, if I understand it correctly, is wrong.


The home wiring is connected to the front-plate, so when I remove the
front-plate, it disconnects all home wiring, leaving just the test socket
on the master box which is what I am plugging into. Into this socket I
have plugged 2 modems (not at the same time), both with and without 3
different microfilters. The SNR/LoopAtt doesn't change with or without
the microfilters, but with the microfilters I hear hiss/crackles when
the ADSL modems start their synchronisation process.

I don't want to sound like a bit of a know-it-all, but I sell and
install ADSL as part of my business and have done dozens of installs
and home/office phone/network re-wires. I have the proper tools and
I've a good level of clue about phone wiring and so on, and how to
trouble shoot it all back to the BT master box. I've done all this in
my case and it's still not right, now I'm looking for clues as to what
the external issue might be.

Yes, I know filters and modems can fail, but right now I've tried
4 filters and now 3 different modems, all with the same results. As
soon as the modem starts to negotiate, the audio part starts to hiss
and crackle and I'm of the opinion that this is caused by some sort
of external failure in either the line or equipment at the exchange,
however getting BT to acknowledge this and not charge me a 100 quid
call-out fee is what I'm trying to do.

That said, your test putting the filter into the test socket and
plugging the telephone into the filter's phone socket (you did this,
didn't you?),


Yes I did. I may not have made that clear, but I was (currently still
am) plugged directly into the test socket.

with the modem in the filter's ADSL socket, should have
removed the ADSL signal from the phone. You are close to the exchange,
so I'd try putting more than one filter in series with the telephones.
This is because filters aren't sharp cut-off devices so the lower
frequency ADSL signals may still be audible (I used to work with a
"golden ears" who could hear cross-talk at -60dB) You can get filters
with sharper cut-off characteristics that perform better on short lines
than the standard design.


My concern is not so-much for the hiss/crackles I hear on the phone, but
that the ADSL modem signals are causing it via some line fault - either a
bad connection or some sort of high resistance, corrosion, diode effect
(???) or equipment failure at the exchange that's being triggererd
somehow by the adsl modem signals.

I can trace my wire visibly from the master socket to the pole where it
goes underground to the exchange..

Also, try disconnecting the pin-3 ring wire. It may be picking up the
ADSL signal and coupling it into the phone side of the wiring (but not
likely if you did the test socket connection correctly...)


It's not connected at all. I normally only have one telephone device
connected and that's a PBX. My home/office phones are on the other side
of the PBX. Right now, it's not connected, just my test phone.

ADSL filters do fail. They have capacitors in them which can change
characteristics with age (and high ring signals). Try a new faceplate
filter. I've had good performance with ADSLnation ones - but they also
will age...


I've tried 4 so-far and 3 modems. One (filter) was brand-new out of the box.

Gordon
  #6  
Old September 29th 08, 12:03 PM posted to uk.telecom.broadband
nospam
external usenet poster
 
Posts: 82
Default What sort of fault might this be?

Gordon Henderson wrote:

With the modem/router turned off, the phone line is clear, but as soon as
I turn the router on and it starts to sync the line starts to sound hissy
with the occasional crackle.


Very likely a bad connection in your line. Corroded metal to metal contacts
can be non-linear allowing high frequency ADSL signals to mix and produce
products in the audio range.

A dirty connection with non-linear leakage between the lines can give the
same effect and is perhaps more likely to crackle but I would expect it to
crackle without an ADSL signal. Dirty connections are sometimes influenced
by humidity and are sometimes temporarily cleared by the higher voltage of
incoming ringing.

A friend had the same problem. All the BT tech could do is remake every
connection till he found problem, it was in a junction box about 1/4 mile
away.

--
  #7  
Old September 29th 08, 12:09 PM posted to uk.telecom.broadband
Gordon Henderson
external usenet poster
 
Posts: 797
Default What sort of fault might this be?

In article ,
nospam wrote:
Gordon Henderson wrote:

With the modem/router turned off, the phone line is clear, but as soon as
I turn the router on and it starts to sync the line starts to sound hissy
with the occasional crackle.


Very likely a bad connection in your line. Corroded metal to metal contacts
can be non-linear allowing high frequency ADSL signals to mix and produce
products in the audio range.

A dirty connection with non-linear leakage between the lines can give the
same effect and is perhaps more likely to crackle but I would expect it to
crackle without an ADSL signal. Dirty connections are sometimes influenced
by humidity and are sometimes temporarily cleared by the higher voltage of
incoming ringing.

A friend had the same problem. All the BT tech could do is remake every
connection till he found problem, it was in a junction box about 1/4 mile
away.


Right.

But how to get BT to actually do something about it though )-:

It might even be worth the 100 quid if I could actually get BT to do
this...

Gordon
  #8  
Old September 29th 08, 12:22 PM posted to uk.telecom.broadband
John Weston
external usenet poster
 
Posts: 108
Default What sort of fault might this be?

In article ,
says...


I don't want to sound like a bit of a know-it-all, but I sell and
install ADSL as part of my business and have done dozens of installs
and home/office phone/network re-wires. I have the proper tools and
I've a good level of clue about phone wiring and so on, and how to
trouble shoot it all back to the BT master box. I've done all this in
my case and it's still not right, now I'm looking for clues as to what
the external issue might be.

Yes, I know filters and modems can fail, but right now I've tried
4 filters and now 3 different modems, all with the same results. As
soon as the modem starts to negotiate, the audio part starts to hiss


Ah - the essential information :-) You can often hear the ADSL modem
until the line synchronises.

I assume you are using a basic phone and have tried different types.
Some older electronic types were not designed to reject even the low
level filtered ADSL signal. Have you tried filters in series to get a
sharper cut-off? - but that won't help is it is noise in the audio
band.

It does sound like a line problem causing cross-modulation. IME, it's a
b****r to get fixed if you don't have a technically competent ISP - and
Openreach engineer interested in fixing the fault. Can the noise be
heard at the other end of a phone call? If so, it is somewhat easier
to get the fault acknowledged.

Good look - and let us know if you find, or get a fix...
--
John W
Replace the obvious with co.uk twice to mail me
  #9  
Old September 29th 08, 12:46 PM posted to uk.telecom.broadband
The Natural Philosopher
external usenet poster
 
Posts: 1,000
Default What sort of fault might this be?

nospam wrote:
Gordon Henderson wrote:

With the modem/router turned off, the phone line is clear, but as soon as
I turn the router on and it starts to sync the line starts to sound hissy
with the occasional crackle.


Very likely a bad connection in your line. Corroded metal to metal contacts
can be non-linear allowing high frequency ADSL signals to mix and produce
products in the audio range.


Reading the thread I couldn't see a mechanism that would cause this..but
yes, you are exactly right here.



A dirty connection with non-linear leakage between the lines can give the
same effect and is perhaps more likely to crackle but I would expect it to
crackle without an ADSL signal. Dirty connections are sometimes influenced
by humidity and are sometimes temporarily cleared by the higher voltage of
incoming ringing.

A friend had the same problem. All the BT tech could do is remake every
connection till he found problem, it was in a junction box about 1/4 mile
away.


The problem is getting Openreach and the ISP to accept they have a
fault..Test equipment should see the fault though.

  #10  
Old September 29th 08, 03:10 PM posted to uk.telecom.broadband
John Livingston
external usenet poster
 
Posts: 38
Default What sort of fault might this be?

John Weston wrote:

Ah - the essential information :-) You can often hear the ADSL modem
until the line synchronises.


I'd dispute that - you shouldn't hear anything, even during modem
training. If there's an audible hiss, then there's a fault- probably an
HR on the line (or possibly a dud filter, of course, but I believe that
the assertion of "Faulty filter" is far too often used to fob off the
customer).

I assume you are using a basic phone and have tried different types.
Some older electronic types were not designed to reject even the low
level filtered ADSL signal. Have you tried filters in series to get a
sharper cut-off? - but that won't help is it is noise in the audio
band.

It does sound like a line problem causing cross-modulation. IME, it's a
b****r to get fixed if you don't have a technically competent ISP - and
Openreach engineer interested in fixing the fault. Can the noise be
heard at the other end of a phone call? If so, it is somewhat easier
to get the fault acknowledged.

Good look - and let us know if you find, or get a fix...


I had EXACTLY these fault symptoms. They were caused by an HR (High
Resistance) fault on the line, either in the distribution pole or the
cabinet. The Openreach engineer fixed it by reterminating the
connections at both points (6 connectors in total - about 10 minutes work).
The engineer didn't actually find which one - it's very difficult to
trace as noted - but he certainly cleared the fault. 284 hours so far at
2464Kb, and NO resyncs at all.

The only fly in the ointment is that BT then tried to charge me for the
callout - but that's another story (see the other thread on this).

John

 




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