Those green boxes on the corners

Discussion in 'Broadband' started by David Hume, Nov 1, 2015.

  1. David Hume

    Davey Guest

    If it fixes the problem, though, is that not a good thing rather than
    bad news?
     
    Davey, Nov 3, 2015
    #21
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  2. David Hume

    David Hume Guest

    I can't see anything on the report which confirms that my line goes to
    the exchange. Perhaps it would mention cabinets if there were a cabinet
    involved? At the top it says "telephone number .. on Exchange
    ...". Perhaps that would be different?
     
    David Hume, Nov 3, 2015
    #22
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  3. David Hume

    Andy Burns Guest

    Yes, if you were on a cabinet, it would mention the cabinet number.
     
    Andy Burns, Nov 3, 2015
    #23
  4. David Hume

    Chronos Guest

    It's a bad thing. Such a "fix" will only ever be temporary.
     
    Chronos, Nov 3, 2015
    #24
  5. David Hume

    Martin Brown Guest

    It is bad because it usually fixes it for just long enough to be a real
    nuisance and it will fail again the next time it is wet or windy.
     
    Martin Brown, Nov 3, 2015
    #25
  6. David Hume

    Martin Brown Guest

    If it says on Exchange then you are an EO line -
    otherwise it says your line is on Cabinet N.
     
    Martin Brown, Nov 3, 2015
    #26
  7. Indeed, it is called time domain reflectometry. See: -
    https://en.wikipedia.org/wiki/Time-domain_reflectometry
    Not always that high. A chap I know designed such a device for use on the original [thick] Ethernet. The pulse was 1V and done in a way to fool all the devices that the net was busy.
     
    R. Mark Clayton, Nov 3, 2015
    #27
  8. You can check the distance to a short circuit or open circuit along a
    75 Ohm co-axial cable using nothing more than an ordinary analogue
    video signal and an oscilloscope. The signal is 1V including 0.3V sync
    pulses and there is no danger of it healing intermittent faults. You
    just need to know how to measure the duration of reflections on the
    scope, taking a value of 200 metres per microsecond for the speed.

    Rod.
     
    Roderick Stewart, Nov 3, 2015
    #28
  9. David Hume

    David Hume Guest

    No it just says on exchange. There is no mention of cabinets. It says I
    can have up to 17 Mbps WBC ADSL 2+, ~ 2+ Annex M.
     
    David Hume, Nov 3, 2015
    #29
  10. David Hume

    Bill Ward Guest

    Can the Roo lead me to my cabinet? I have no idea where it is despite
    having walked round the area. The BT map shows it somewhere between the
    corner of the street we're on and what cannot be more than 200 yards
    along the road.
    Bill.
     
    Bill Ward, Nov 3, 2015
    #30
  11. David Hume

    Woody Guest

    Question: what maps and where do I find them? I know I am on cabinet 8
    but where is it is my problem? Plenty of clearly marked VM cabs but
    what there of BT seem to have no marking in the main.
     
    Woody, Nov 3, 2015
    #31
  12. Sometimes. Usually there will be a BT (or GPO) inspection cover close by in the pavement.
     
    R. Mark Clayton, Nov 3, 2015
    #32
  13. David Hume

    Woody Guest

    Umph! I know that Mark, but its still doesn't help me identify the cab
    number!
     
    Woody, Nov 3, 2015
    #33
  14. David Hume

    Roland Perry Guest

    First thing to do, if you are connected via a pole, is look at the trail
    of A3-sized BT manhole covers in the pavement leading one way or the
    other.
     
    Roland Perry, Nov 3, 2015
    #34
  15. David Hume

    Bill Ward Guest

    Bill Ward, Nov 3, 2015
    #35
  16. This page is dated 2011. The text begins "BT has created a map showing
    which exchanges are in line to be enabled for its fibre-to-the-cabinet
    Infinity broadband" but there is no hint as to where, if anywhere, we
    can download or even look at the map.

    If you want to know where your local BT boxes are, it seems there is
    no other way than to do some research yourself. Put a few sample
    addresses near you into the DSL speed estimator and see which way the
    "speed gradients" go on a map, then have a look around on Google
    Street View where the speeds are highest. If you find a box by this
    method, make the final check by going to the box in person and looking
    at it, because the images on Google can be several years old. The
    boxes usually have numbers painted on them.

    Rod.
     
    Roderick Stewart, Nov 4, 2015
    #36
  17. David Hume

    David Hume Guest

    I wondered around my locale on street view, and found a cabinet. There
    was a church near by, so I googled its telephone number, then put it
    into dslchecker. The church is connected to an exchange via a
    cabinit. The exchange is 5 or 6 miles away, even though the church is
    nearer to the local exchange that I am connected to than I am. It says
    the church can get 80 Mbps.

    How has this system come about? Why are some places connected to
    cabinets and others directly to the exchange?
     
    David Hume, Nov 4, 2015
    #37
  18. David Hume

    Roland Perry Guest

    That'll normally be because when they had a phone installed the nearest
    exchange was filled up.
    That'll be using "Infinity".
    The one connected direct to an exchange are the ones where the cable
    length is short enough that the pole it needs to reach is closer to the
    exchange than the first cabinet in that general direction.
     
    Roland Perry, Nov 4, 2015
    #38
  19. David Hume

    Bill Ward Guest

    Here is the up to date one
    http://www.superfast-openreach.co.uk/where-and-when/
    Bill.
     
    Bill Ward, Nov 4, 2015
    #39
  20. David Hume

    Phil W Lee Guest

    Lack of coordination, coupled with a universal service obligation and
    a very slow rollout.
    first there was an exchange, and the dozen or so places that had
    phones all connected directly to it.
    The number of subscribers grew over time, until (in various locations
    and at different times) it became sensible to run a fat cable to a
    cabinet, and distribute smaller cables from there. Existing lines
    which went direct to the exchange wore not moved to the cabinet
    though. Then as cabinets fill up, cables are run from the nearest
    cabinet with spare capacity, instead of a full one that's closer. Add
    a bit of customer churn, and you get the mess we have now.
    Of course, it could be improved, but it would cost a fortune to do so,
    and would inevitably interrupt service to some people as their
    connections were moved.
    It's a bloody miracle it even works for voice, never mind data (which
    it was never designed for).
    These are the same wires we used to think we were lucky to get 1200/75
    baud modems to work over, and now we feel hard done by if we can't get
    10,000 times that!
     
    Phil W Lee, Nov 4, 2015
    #40
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