Damp Telephone Lines?

  Procrastinus 09:02 30 Mar 2008

This is one for any BT engineers!
We live in Fance and have constant interruptions lasting several days to our dial up service. It always seem to occur after rain and this leads us to suspect damp penetration of the lines. Service returns to normal after a few days of dry weather.
However the phone (operating off the same wall socket) works fine all the time. The Dell XP dials properly but the just cannot connect during the problem days. The computer, modem have all been checked so has our ISP, which just leaves France Telecom, who of course say they cannot find a fault as the phone works.
So - does the computer require more from the phone line (even on dial up connection) than a phone? Is my thoery of damp penetration feasible?
We live about 4 kms from our FT Junction Box and the lines are generally poorly maintained with broken hooks leading to possible rubbing and insulation damage.

  Graham. 10:35 30 Mar 2008

A dial-up modem uses voice frequency. Try connecting it to the working phone socket.

Also, break dial tone on the phone by dialling a digit, then listen for noise.

In the UK, the line provider has to supply a line capable of supporting dial-up at a minimum speed. See if the French regulator has a similar rule.

  Cockney Rebel 11:01 30 Mar 2008

Your theory about damp in the lines is definitely possible.Water can get in via a poorly sealed cable joint.Also if there is a damage on the cable elsewhere water ingress can take place.If as you say it happens mostly during rain it leads me to suspect it may be due to damage on the cable feeding your house.Possibly caused by hungry squirrels! if it passes through trees.May also be caused by the cable rubbing on tree branches.Hope this helps.

  Procrastinus 13:47 30 Mar 2008

Thanks Graham, I will check regulator and the computer shares the same socket as the working phone.
Thank you also Cockney Rebel, this is what I also suspect as the standard of line maintenance would disgrace a housewife's washing line! Loads of repair joints and cables unhooked from their posts. I did take in some photos of the state of the lines to our local France Telecom office and the result was 'electric'!! Pray for no more rain!

  polymath 19:53 30 Mar 2008

Might be worth getting your wall socket checked too, 608. We had similar problems intermittently in wet weather for years, until we got a telecom engineer who didn't like being beaten, and opened up the wall socket (nobody else had in its 15-year life). I couldn't hear most of what he said to his assistant, but gathered that he was conveying his opinion of the original installer in a forceful manner. The way the wires came in from outside channeled water into the socket, and using the line for a few moments activated a short-circuit, which cut us off.

A new, better installed socket did the trick, and it also improved my dialup connection. I'd been constantly losing it, even when the phone was working. Whenever I rang the phone company here (in Ireland), they detected some noise on the line (I hadn't noticed it). It didn't usually affect phone calls, but they said it was enough to faze internet connections, which are more fussy about noise. They'd tried all sorts of exterior checks before the engineer came inside the house and solved it.

I'd keep trying with France Telecom until you happen on someone who doesn't just want you to go away. Being able to make a voice call doesn't prove the line's good.

Don't rule out the animals etc though - it's cows here that are sometimes the culprits. They occasionally choose a route necessitating rubbing past a certain relephone pole and putting too much strain on the wiring. It took Eircom quite a while to figure that one out!

  2bathred 20:07 30 Mar 2008

Any and all joints in telephone cables are potential faults. Even if the weather is dry the moisture from a previous wet period would cause corrosion especially as the wires will be copper conductors. This is known in the telephone trade as HR joints ( High Resistance) This will raise the natural line resistance of your connection and @ 4Km from the junction box plus the distance to the telephone exchange could be a problem. In GB the line length is usually a max of 3 miles approx 6Km (? haven't got the hang of metric yet)
Get the line tested when it is raining.
(Retired BT engineer)

  Procrastinus 08:50 31 Mar 2008

Hi polymath and 2bathred. Kind of you both to reply.
Internal sockets are actually brand new but I do agree with your point about line strain. With France Telecom it seem sometimes that the wires hold up the poles - the curse of privatization? -another debate! In fact a FT engineer came out to check in the rain and when the internet was inoperative but the phone was working. Lots of Gallic
shrugs, mutterings and it's everyone else's fault! They all say 'problems with living in the countryside' to which I reply '21st century'. I shall continue to make a nuisance of myself until it is all sorted, but it is very useful to have some professional ammunition.

  Graham. 09:32 31 Mar 2008

Ask FT if any of your connection to the exchange is over aluminium underground cable. That is particularly susceptible to damp, and has all been replaced by copper in the UK.

  amonra 14:58 31 Mar 2008

All Aluminium replaced ? You've got to be joking ! My telephone socket is about 300 mtres from a length of aluminium cable which causes no end of poor connections, noise, high resistance etc. BUT of course BT denies all knowledge of it. There is one town near here which is LOADED with aluminium lengths. "Which will be replaced shortly "

  Graham. 15:22 31 Mar 2008

Thanks for the clarification, I wasn't sure so was expecting a response.

There's nothing wrong with aluminium, it's the electrolytic action with copper in the joints. When they get damp, the resistance (and noise) increases.

  polymath 20:58 31 Mar 2008

I didn't know aluminium was sometimes used for phone lines! Copper does has a value of course, but could BT (or its predecessors) have saved that many shillings? Or could it have been a postwar Austerity thing? Perhaps that's what happened after WW2 to the bombers that all those aluminium saucepans etc were sacrificed for?

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