BT ADSL V1.0 faceplate - no need for microfilters?

Discussion in 'Broadband' started by Martin Underwood, Sep 23, 2005.

  1. I was at a customer's house yesterday putting the finishing touches to a
    broadband installation now that the line had been activated.

    BT had installed an ADSL V1.0 faceplate (I think that's how it was labelled)
    when they were doing some other work for her.

    I'd bought microfilters, but it suddenly dawned on me that broadband was
    working fine even before I'd inserted them: there was at least one
    unfiltered telephone on the line.

    So does an ADSL faceplate cause the rest of the house wiring (out of the
    back of the socket) to be filtered? I'd assumed that it was just a socket
    and microfilter combined - that its two outputs would be filtered and
    unfiltered respectively but that the rest of the house wiring from the back
    of the socket would be unfiltered and would need microfilters.

    As it happens things have worked out well and the customer has avoided £6
    apiece for the three microfilters. However there's a more important aspect:
    if a house has an ADSL faceplate, does that mean that unless BT remove it,
    you are restricted to only connecting your router/modem to that one place
    and can't re-site it at any other phone point in the house?

    As a matter of interest, are manufacturers going to start incorporating ADSL
    filters into new phones, fax machines etc to avoid the need for separate
    Martin Underwood, Sep 23, 2005
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  2. Martin Underwood

    Phil Guest

    Yes, all extensions wired to the back of this faceplate is filtered. I
    have one of these faceplates (installed before the availability of
    You could always run an extension cable from the RJ45 socket, or get
    hold of the lower part of an NTE5 master socket and fit it yourself.
    Phil, Sep 23, 2005
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  3. Martin Underwood

    Lurch Guest

    Not using filters doesn't necesarily mean that broadband won't work,
    it just means that the connection may be unreliable and\or there is
    noise on the line when you're trying to make\receive voice calls.
    There are 2 types of ADSL faceplate filters available for the BT
    master sockets. One just has terminals on the back which are filtered
    to provide a filtered feed to extension wiring and the other type are
    the same but with the addition of unfiltered terminals so a seperate
    pair can be run to a specific unfiltered socket for use with the ADSL
    modem. ADSL Natrion and Clarity both do ADSL filtered sockets abnd
    ADSL Nation have a range of filtered and unfiltered extension sockets
    so you can get rid of dangly filters for evermore!
    No, if it's a lower half replacement of the NTE5 then you can remove
    it, change it for a modified one and put the modem elsewhere.
    Doubtful as a) it would add cost to the product b) they'd use the
    cheapest components possible and anyone with marginal levels on the
    ADSL line would have to buy additional filters and top quality phones
    to be able to get it to work c) the same product is generally shipped
    pretty much worldwide in some cases so ADSL filters would probably be
    useless for the majority.
    Lurch, Sep 23, 2005
  4. Martin Underwood

    thoss Guest

    Yes, broadband would be working, because this is never normally
    filtered. The function of an ADSL filter is to keep the ADSL signal
    away from the phones.
    thoss, Sep 23, 2005
  5. My point was that broadband requires its signal not to be shorted through a
    phone - hence every phone must be isolated from the ADSL-enabled line by a

    As others have pointed out and I hadn't realised, an ADSL faceplate filters
    not only the output at the BT socket on the faceplate but also the rest of
    the house wiring between the master socket and any other sockets.

    I realise that the RJ11 ADSL socket is unfiltered: a router could be
    connected directly to the BT line without needing a microfilter: it's only
    when you start connecting phones, faxes etc that you need filters.
    Martin Underwood, Sep 23, 2005
  6. Martin Underwood

    Kraftee Guest

    Not quite, as the filter can & does put some loading onto the ADSL
    circuit (if you Google back over the last year or so you will find a few
    such postings have been put on this very group, where peoples routers
    wouldn't work unless they were connected via a filter). Also some
    customers have experienced problems when they receive calls from one of
    the many infamous random number dialers used by tele sales companies
    with the call causing the router to loose synch. Which is one of the
    reasons why some broadband customers (who are using the line only for
    the BB connection) order ICB lines (I've even met up with a few OCB &
    ICB lines on certain projects)
    Kraftee, Sep 23, 2005
  7. Martin Underwood

    Graham Guest

    All the ADSL filters I have examined have the ADSL port connected directly
    to the line and have a low-pass filter connecting the line to the POTS port.

    Are you saying that you know of a filter that contains a high-pass filter to
    pass the ADSL?

    Have I misunderstood what you said about Tele-sales diallers? How can one
    type of incoming call cause your router to lose sync and others not?

    Also were the lines with OG and IC call-barring provided "in house" for BT?
    I thought BT wouldn't supply a line exclusively for ADSL


    Graham, Sep 23, 2005
  8. the filter circuit does sit across the line though

    so some interaction of a filter with the ADSL is possible.

    Phil Thompson, Sep 24, 2005
  9. Martin Underwood

    Kraftee Guest

    Any circutry connected will make a difference, no matter how slight, &
    as I have already said there have been cases reported on this very group
    over the last 12 months were ADSL routers would not synch when
    connected directly to a line, but did when connected thru a filter...
    No & you know I'm not...
    ANY type of calls, I used telesales random dialers as an example where
    calls to lines, which normally wouldn't receive calls, can happen.
    Think again,

    Try just reading & not trying to pick holes in other peoples posting
    dear chap...
    Kraftee, Sep 24, 2005
  10. Martin Underwood

    Kraftee Guest

    Kraftee, Sep 24, 2005
  11. Martin Underwood

    Graham Guest

    No problem Kraftee, simply inviting clarification on a few points which you
    have now given.
    I wasn't trying to flame you, although with three issues in a single post,
    you may have thought otherwise.
    On the contrary.
    I will continue to read your informative posts, made, no doubt, with some
    risk to your position with your notoriously secretive employer.


    Graham, Sep 25, 2005
  12. Martin Underwood

    Kraftee Guest

    SSSSHHHhhh you don't know who's reading... :)

    No problem, it's just that some of the issues have come up before & I
    have been flamed for posting what is reality & not followed the current
    latest theory. Funny how most of those posters have now either gone
    away or have become a lot quieter though...
    Kraftee, Sep 25, 2005
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