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Copper Phone line problems

Discussion in 'The Pub' at netrider.net.au started by vic, Aug 5, 2009.

  1. Folks,

    Is anyone an "expert" on the copper wire that is buried in the ground that provides us with ADSL & Telephony services?

    Reason I ask is that when I built this house, the Downer Engineering contractor turned up earlier than booked and laid the phone lines.

    Unfortunately for me, when the plumbers were finishing off they broke the phone lines.

    They were repaired and we proceeded to move in.

    When I had the ADSL connected here 1500/256 it was slow, real bloody slow, unusable in fact. I complained and a Telstra tech came out and inspected the phone line after I insisted that it be checked due to the break/repair.

    He found the repair was dodgy and full of water. He repaired the phone line and my speed returned. Hovering around the 1.2MB/s mark.

    I then upgraded to the ADSL+ service the 8000/1500? plan. I was getting around the 4.5MB/s which was a shit load faster than my 1.2 that I was on previously.



    I decided to go to ADSL2+ about a week ago but my speed did not increase, in fact it went backwards slightly initially.
    After much mucking around with the modem, I've managed to get a stable connection and one that is around the 4.5-4.9MB/s with a 15ms ping result and an upload of 0.88MB/s.

    Long winded, I know, sorry, but.........

    Now my question is, when the copper was broken, it obviously wasn't cut with a pair of side cutters.
    It was dug up and therefore stretched until it broke.

    So for those that are in the know, will this affect my speed?
    Will the stretch in the copper affect the way the little 1's and 0's flow along the line?

    I guess ultimately I'd like Telstra to replace the copper in the ground so I can eliminate that as being a factor in the lack of speed.

    I'm happy to accept the piss poor speed if every variable has been looked at.

    Anyone have any advice, thoughts, ideas etc.?????
     
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  2. others would be more qualified to answer, but i would say it would depend on how much it stretched, and maybe how much the grain structure changed. Just guessing on that, because I dont think grain structure impedes the electrons. These days, circuits are being designed where the metal wire is atoms thick, any thinner and the resistance starts becoming overbearing. So even if the final repair job is bodgy, it should still let the electrons flow just fine. my adsl 2 speed is pretty much the same. maybe a bit higher, bu tnot much. how far are you from the exchange?
     
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  3. I'm about 3 KM from the exchange.
     
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  4. From memory I think that distance knocks a good bit off ADSL2 speed, more so than ADSL.

    According to the TPG site the people in my neighbourhood get around 8 m/bit D/L speed on ADSL2, and that's about 1km, which also puts me just outside the coloured zone where the speed is rated higher.

    It might be worth a look at your neighbourhood results, since it's coming down the same wire. If one carrier averages higher or others near you are consistently better served it might give you some useful intel.

    Not sure about the stretching, but a join is always a potential glitch, though done right it should be fine.
    Maybe the stretched cable has some breaks (presuming it's multistrand?).

    If you haven't already, you could try whatever internet connection optimizing software you can get your hands on. Some of them tune the setting automatically and some let you tweak manually. I recall that there had been some good improvements from playing with the size of the data packets. I think if the line is good (ie. low bit error rate), bigger chunks are fine and save on overheads, but if you have more errors from noise/interference/crap wires, smaller packets mean less big chunks have to be resent.
     
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  5. Close Lilley.

    The resistance in an electrical conductor (the copper wire) is directly inversely proportional to the area of the conductor.


    R = ( ro * L ) / A

    R = Resistance in [ohms]
    ro = Resistivity of material (different for all metals and conductors)
    L = Length
    A = Cross-sectional Area.

    So if the wire was stretched to breaking point, it is fair to assume the conductor has thinned out over a certain length before it broke. This increase in resistance could be having an affect on the line speed.

    I'll do some more research today Vic and sus it out. I have no other work to do and at least this is remotely related to my work rather then motorbike forums... =P

    Side note, I remember a tel-comms lecturer once rabbiting on about ADSL on copper lines and something to do with suppressing magnets placed over the cables which were installed for the use of phones before ADSL was invented then had to be removed (for the use of ADSL)... (similar to the thingo's you find on power supplies for your laptop etc).
     
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  6. A half decent ADSL router will tell you the estimated attenuation on the line from the exchange and the SNR. 3KM should give you almost perfect ADSL2 connection speeds on a good line. I would have thought the Telstra lad would have tested for these figures?

    Anyway - you don't need Telstra to pull a new line, any certified electrician/cabler can do it. Telstra may need to make the connection in the pitt though. Ask them to run cat5 or better if there isn't already.

    Having said that - do you have a central splitter? Have you tested the modem/router at the first point in the line with all other phones and things removed from the line? Tried a different modem/router?
     
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  7. Your speed is limited by the total attenuation on your circuit and the fact that you are getting very similar speeds on 8MBit ADSL1 and 24Mbit ADSL2+ says that your attenuation is such that your sync speed is the limiting factor.

    Since your sync speed is the limiting factor there isn't a whole lot you can do about the whole situation however as previously mentioned getting a tech out to replace your lead in and fitting a central filter will minimize that section of the loss that you have any control over.

    I had a similar situation when I was living at Campbells Creek, my modem reported a line attenuation of 56Db and my sync speed wasn't slightly less than 4 Mbit.

    At a 4Mbit sync speed you won't see any advantage with ADSL2+ over ADSL1 speed wise although if you are lucky enough to be with an ISP's own DSLAM in the exchange you will have other benefits such as selectable line profiles, cheaper cost and higher quotas.
     
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  8. I've just had a read of this, and to summarise, it says the same things Sooty and ZRX1200R have just mentioned.

    The only things I would suggest you could basically and quickly look at would be whats operating around the modem, the cable between the modem and wall, and how many phones you've got plugged in. Eliminating basics like this will most likely do nothing because as previous mentioned, it sounds like your line attenuation is your limiting factor.

    So short of having a new lined pulled, you'll have to sick to your current speed of downloading p0rn vic... :p


    Still looking for that magnets thingo... When was the estate built / copper lines pulled through do you know?? Exchange age?
     
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  9. http://www.internode.on.net/residential/broadband/adsl/extreme/

    If you check out that link above, you can see the speeds drop considerably from about 2k onwards. I was 3k from the exchange and would sync at about 8mbit, I would expect that if you are 3k from the xchange, the actual distance would be about 3.5k, and you'd sync at about 6Mbit.

    Are you using Telstra for your ISP? Other ISPs often let you manage what profile is used at the DSLAM which can improve performance and reliability.

    Have you tried isolating the modem from all other devices on the phone line? ie, disconnect every phone device, remove the filter, and plug the modem directly into the socket.

    Many houses have a splitter installed to split the line to different extensions, sometimes that can be dodgy and easily fixed.
     
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  10. All of the above.

    3km is a little long for anywhere close to max ADSL speeds. There are lots of things that come into play.

    You could be on a RIM.
    RIM's are installed in most new residential developments by Telstra. This used to be a real problem as they were ADSL and bandwidth limited. All a RIM does is effectively terminate your copper in a small street box which is then fibre'd back to the main exchange. However, Telstra do this to avoid having to lay lots of new copper and so you get lots of people on the sam RIM, all wanting their ADSL2+ speeds. Works great until Telstra sense a bottleneck and so they throttle you ALL back to 3mbps. All this assumes your RIM is ADSL2 capable.

    Line attenuation too high.
    Combination of line length of other environmentals.

    Damaged Cable.
    Will dramatically impact the Signal to Noise ratio. As ADSL is carried over standard copper, the noisier it gets (and litteral cracking is the most noticeable symptom) your line speed drops as a result, trying to get a stable speed.

    Internal cabling faulty.
    A central splitter will help isolate any dodgy internal telephone sockets.

    Unfiltered phone
    It only takes one telephone device to be unfiltered (Foxtel for instance) and you've got signal degredation. Likewise, any sockets that you don't use, try to get them uncabled. The more cables you have, the greater chance to impact speed.

    Lastly, use this website to check your line of sight from the exchange, whether you are on a RIM and if that RIM is ADSL2 capable.

    http://www.yourbroadband.com.au/
     
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  11. I'm 4.6km from my exchange and achieve 18mbit/sec. 3.2km of copper, the rest aluminum. There are many variables at play - I think that chart is quite conservative which is understandable.
     
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  12. There certainly are, but if you are on an uncongested ADSL2+ RIM and that RIM is at the bottom of the road, your effective copper length is only a few hundred metres.

    I am about to move from the arse end of the World (TW port, ADSL2+ 18mbits) to a smart address. The RIM is 50m away, but only ADSL1. Telstra sucks ballz.
     
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  13. Obviously if the wire has been stretched the speed will drop; the electrons have further to travel :LOL:.
     
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  14. I've dealt with a few sites that were hooked into RIMs. They usually show an excellent connect speed but slower actual throughput. Afaik most mini-cmux units are capable of ADSL2+ but Telstra may artificially limit them to ADSL1 or throttle speeds.

    Telstra must provide 100% capacity to voice services before adding data so for example if a cabinet has 1Gbit available to it and all the voice connections 'could' use up to 500Mbit then there will only be 500Mbit available for data use, share that among the 96 physical connections using a very basic method...
     
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  15. Vic would hang off either Werribee (built in the 60's) or Tarneit Exchange (early 80's replacing several old huts near Werribee Plaza SC)depending on where his house is, the age of the exchange isn't a factor as the internal infrastructure has been replaced since the days I worked at both sites (late 80's / early 90's).

    The age of the cable sections in the ground is a factor as is the quality of the cable joints along the way, some main cables leaving the exchange might be nearly 30 years old but the ones to Vics house would date back to when the estate was built.

    Telstra just keeps adding stuff as required, in some older areas of inner suburbia the in ground cables are over 80 years old and still going strong.
     
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  16. pvda, you might be able to help me.


    Back in my uni days a tel-comm's lecturer was rabbiting on something about magnets or toroid coils or something been placed over the cables to prevent noise (for the human voice bandwidth). These magnets / coil things would drastically increase the attenuation (if I remember rightly) a bit after 4kHz. When these were placed ADSL had not been invented or thought about for public use as he explained.

    Once ADSL was brought into wide spread public use they realised they must remove these magnets / coil thingos. That's the best my memory serves me. What I'm getting at is that those things might still be attached if they are old cables?? That was the only other idea I had on it... any knowledge of what my lecturer might of been yammering about??

    Cheers
     
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  17. Loading coils - generally used on very long copper runs. They minimize echo, attenuation and the effects of EMR. If you have coils on your line, then you're probably not going to get DSL even with them removed.
     
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  18. Yerp.

    Moved into a new place, I'm about 2km worth of actual copper to the exchange, and I'm hoping for blazing speeds.

    At any rate, it really sounds like Vic has a legitimate complaint here. I don't know what he can do to fix it, though.

    Vic, make sure you do the isolation test. Then:

    You might have to pay money to have the line actually tested and inspected, but if you're like me you'll just want a working, non-sucking, internet connection.
     
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  19. What he said :)

    You've got to remember that some country phone services could be a 20km copper cable run and that's where the loading coils help.

    You'd be amazed the interference caused by crook connections on electric fences or even the problems for those who live near the ABC 3LO transmitter between St Albans & Sydenham have with the 3LO broadcast being induced int otheir phone calls :shock:
     
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  20. Vic, in real terms the speed you are getting on adsl2 is about right for the distance from the exchange.
    The difference will be the cheaper cost, naked dsl and phone and increase in download limits as opposed to adsl1 and the 8MB service.
    I live 2.4 kms from the exchange and get 10MB service.
     
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