Still Confused About Fibre

Discussion in 'Broadband' started by Jim, Jul 24, 2014.

  1. Jim

    Kraftee Guest

    oops curtilage (don't you just love smell checkers)
    Kraftee, Jul 26, 2014
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  2. Jim

    Mark Carver Guest

    Surely BT Openreach have mearly 'adopted' Brian's extension cabling, and the
    new demarkation point is the newly installed master socket ? If they (aka the
    BTO engineer) were happy the cable meets spec, what's the problem ? My
    parents' master socket, is quite 'deep' inside their dwelling, that's where
    the original 1969 GPO52a junction box for the phone was located. Though BT
    didn't notice I'd replaced the indoor section of dropwire with 1980's 'CW1308'
    and another 52a box at dropwire building entry point, when they fitted a
    master socket in 1985 :)
    Mark Carver, Jul 26, 2014
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  3. Jim

    Roger Mills Guest

    So where's the demarcation point, when the drop-wire enters the building
    and carries on - probably via an intermediate junction box - to a master
    socket some metres inside the building?

    If it *isn't* the master socket, what's the point in having a removable
    faceplate which separates BT's incoming wiring from the customer's
    extension wiring?

    Assuming that the demarcation point *is* the master socket, are you
    nevertheless saying that OR isn't responsible for any wiring on their
    side of the master which happens to be inside the building?

    Incidentally, how are you defining "curtilage"? My dictionary seems to
    think that it includes the grounds immediately surrounding a building
    and not the building itself. That would be even worse!
    Please reply to Newsgroup. Whilst email address is valid, it is seldom
    Roger Mills, Jul 26, 2014
  4. Jim

    Kraftee Guest

    Now you hit the nub of the matter, what used to be acceptable has become
    (and is still becoming) not acceptable, all in the name of cash flow/profit
    margin (and as a aside improving quality, supposedly).

    It used to be acceptable as a quick easy fix but even from the early days
    reverse feeding extensions have and has been causing problems with DSL.
    Despite this fact it has been carried over into the installation of VDSL,
    mainly due to poor training, unreasonable prod stats and just sheer laziness
    on the part of the 'installer'.

    As for demarcation, the argument as to where it happens has been getting
    further and further back from the 'master socket (which is where running
    extensions in the same cable as your feed is a costly no no). If Openreach
    owns the cable feeding the NTE and if the customer owns the extension
    wiring, running both in the small multi core cable can be costly for the end
    user (you don't expect Openreach to cover the cost, willingly, do you?)
    Kraftee, Jul 26, 2014
  5. Jim

    Brian Mc Guest

    : In my case, jelly crimps are used behind the socket at the old master
    : position - and the incoming pair is carried up to the new master
    : position. I assume that the new master is now the demarcation point.

    Precisely the same as my new setup!
    Brian Mc, Jul 26, 2014
  6. Jim

    Jim Guest

    It has 1.5 pairs !

    So that's out.
    Jim, Jul 27, 2014
  7. Jim

    Jim Guest

    I know, I'm sure I left off the ringer wire,
    but can't recall now what the third wire is for
    if it's used at all.

    I don't reeealy want the master socket to be
    Jim, Jul 27, 2014
  8. Jim

    Jim Guest

    I'm not quite sure I follow all that - in fact
    I don't !

    I had thought that, provided the O.R. VDSL modem's
    output socket is a standard ethernet one (whatever
    its RJ number), the installer can just site the VDSL
    modem next to the master socket and leave me to route
    to the modem with a standard ethernet cable.

    It appears from what I can see on picture/diagrams
    of these modems, the output socket is a standard

    I'd use two coupled ethernet cables from the junk-box
    initially while I set the modem up, then replace that with
    a good quality custom made cable from a supplier. I don't
    have the tools or the expertise to fit connectors myself.
    (I have the tool, but the last effort was a disaster and
    I haven't touched it since).
    Jim, Jul 27, 2014
  9. Jim

    Jim Guest

    That was my thinking. I'll order a custom cable
    of just over the correct length and use that. It'll
    be about 20m.

    No rush as I have to have an electrician in to
    install a mains socket near the modem. Expensive
    probably, but neater than temporary cables !
    Jim, Jul 27, 2014
  10. Jim

    Jim Guest

    Where's this democratic society you speak of?

    The mains was not designed to carry RF and
    it shouldn't be there.
    Jim, Jul 27, 2014
  11. Jim

    Jim Guest


    Another spectre arises: VDSL is HF ... possibility
    of interference to radio? I just hope it's a well
    balanced system which doesn't radiate.
    Jim, Jul 27, 2014
  12. Jim

    Jim Guest

    Probably the same way as the OFCom decided
    that we had the best broadband in Europe!

    Leaving countries like France, Germany and Spain
    out their calculations. Like everything else we're
    probably somewhere down in the thirtieth best in Europe.
    Jim, Jul 27, 2014
  13. Neither was the telephone system, but we're using it. Lots of things
    are being used for purposes they were not designed for. Chimneys were
    not designed to support television aerials for instance, television
    was not designed for colour and radio was not designed for stereo.
    Should we just not use these things simply because their present usage
    wasn't planned from the start?

    Roderick Stewart, Jul 27, 2014
  14. Jim

    Ian Jackson Guest

    The big difference is that ADSL over phone lines, chimneys supporting TV
    aerials, colour TV, and stereo radio hasn't* really had any detrimental
    effect to anyone. On the other hand, stuffing wideband RF into the mains
    WILL cause radiation, and this WILL almost certainly interfere with
    existing users of the RF spectrum who live nearby.
    *I admit that if I donned my pedant's hat, I could give examples proving
    that this is not absolutely 101% true, but I'm reluctant to bore you.
    Ian Jackson, Jul 28, 2014
  15. Jim

    Martin Brown Guest

    My master socket is conveniently located in the loft where the external
    wiring drop terminates. I can't detect any measurable difference in
    either SNR or attenuation between a 2m cable up there, a dedicated low
    loss 30m cable or the existing house wiring. Although the latter is more
    complex and very slightly more prone to picking up interference.

    I am only on standard ADSL and the distance to the exchange precludes
    any chance of getting fibre to cabinet service. The nearest cabinet to
    me is further away than the exchange :(
    One advantage of putting your own terminations on the cable is that you
    can pass the cable sans connector through a smaller hole in the wall.
    I'd be inclined to run the signal cable to a convenient location for
    siting the modem rather than do expensive mains rewiring for it.

    Martin Brown
    Martin Brown, Jul 28, 2014
  16. I realise this, but in practice hardly anyone seems to have been
    affected. The only objections to Homeplug type devices that I've seen
    have been in newsgroups such as this one, and generally from people
    with special interests. The only practical evidence I've been able to
    collect for myself, while admittedly not exhaustive, does concern the
    sensitivity of ordinary radio receivers to interference in domestic
    situations, the basis of most of the objections. It suggests that
    existing users of the RF spectrum who live nearby would have to live
    very close indeed, as I can't detect anything more than a few feet
    away from the devices.

    While I'm sure they must produce radiation that can be detected
    further afield with suitable equipment, I haven't seen anything in the
    news about this causing widespread problems. If there really were a
    problem worth the inconvenience and expense of outlawing millions of
    legitimately purchased devices already in use, I'd expect more than a
    few amateur radio enthusiasts to know about it.

    This may not be what you want, but it's reality. I expect all the town
    dwelling amateur astronomers might like the street lights to be
    switched off so they can see the sky, but it isn't going to happen.
    I'm aware of this too. The extra information in colour TV and stereo
    radio signals was added in such a way as to minimise the disturbance,
    while accepting that inevitably it would be non-zero because nothing
    is perfect. Everything has a price. We just have to take *everybody's*
    interests into account when deciding if it's worth paying.

    Roderick Stewart, Jul 28, 2014
  17. Jim

    Ian Jackson Guest

    In these examples, nobody suffered any inconvenience. Nobody could
    seriously claim that the introduction of colour suddenly caused their
    monochrome TV pictures to have significantly less sharpness (although it
    sort-of did, if you looked closely enough), neither could they claim
    that their mono hi-fi reception was screwed up when stereo was added.
    However, some people living close to a PLT system have their reception
    impaired - or even effectively wiped out.

    Also, don't forget that the addition of colour to TV and stereo to radio
    only came about after several years of invention, discussions and trials
    in order to maximise the compatibility with the existing system, and to
    minimise any degradation of existing quality. PLT was originally
    introduced on the basis that no one would be affected - and if they
    were, then tough shit!

    OK, in modern PLT equipment digital notches have been belatedly added to
    minimise radiation on most of the HF amateur bands, but that leaves the
    rest of the spectrum at risk. There simply has to be a better way of
    doing things.
    Ian Jackson, Jul 28, 2014
  18. There's no "sort of" about it. These effects absolutely definitely did
    occur, which is the very point I'm making here.The extra information
    in a colour signal did produce visible (and sometimes audible) effects
    on monochrome reception, and the mono component of a stereo radio
    broadcast is transmitted at a slightly lower level, even if distortion
    of the stereo component doesn't produce any other effects.

    The broadcasters went to a great deal of trouble to establish how to
    add the extra information in such a way as to minimise any adverse
    effects for the majority of viewers and listeners, but accepting that
    these effects couldn't be eliminated completely. If the new
    enhancements (colour and stereo) had messed up reception for lots of
    existing viewers and listeners there would have been a public outcry,
    but thankfully there wasn't. So there are real effects but they're not
    enough to be a problem.
    So where are the news reports of "Reception ruined by neighbour's
    internet"? I don't recall seeing any, ever. What I do recall is that
    when I held a portable radio within about a yard of a Homeplug device
    I could hear a bit of a buzzing noise between stations, and nothing
    when tuned in to a station, and that was absolutely all. In other
    words, there is certainly an effect, but it seems to be no more than
    "detectable but not enough to be a problem". If there are any real
    cases of the sort of electronic wipeout that you seem to fear, and
    anything more than anecdotal accounts of them, please tell us.

    Roderick Stewart, Jul 28, 2014
  19. Jim

    Jim Guest

    That shouldn't be. I'm town edge with open country
    on one side and they've eventually fibred it. Town itself
    came first of course.
    Holes for RJ45 are easily filled in and
    painted over.

    I could do it myself I suppose, but DIY electrics
    aren't a good idea if you're likely to sell your house.
    Jim, Jul 28, 2014
  20. Jim

    Jim Guest

    The main problem is at HF (3 - 30 MHz).
    There is usually little interference above that
    and defence and emergency services using HF are
    usually well outside built-up areas so they don't

    Below HF there's only MW and LW which few seem
    to use nowadays so few complaints are made although
    the interference is severe at MW/LW LF and VLF.
    It isn't just homeplugs of course, it's switch-mode
    power supplies, certain types of TV, motors, power-line
    arcing, thermostats ...
    Jim, Jul 28, 2014
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