Master Face Plate Splitter - Filtered ?

I recently installed a master face plate splitter (see http://www.solwise.co.uk/adsl_splitters.htm) and found that unless I put a 'dongle' filter between the face plate and the phone, the phone is unusable since it sounds like static when I try and talk to someone (at my end, theirs is fine). The ADSL connection is not affected by the phone use.

I thought these face plates were filtered, are they just splitters? I would like to know if either.

1. That is how they work, they are just splitters and you need to connect the phone via a filter.
2. They should filter, mine could be dodgy
3. I might have installed it wrong - difficult to see how, it just screws on.

Thanks for any insight

Adam

How is your signal from the exchange arriving at the faceplate?

Not sure what you mean? The face plate splitter is attached to the master socket.

They're certainly supposed to be filtered, but the Solwise one is a bit cheap and nasty. You would have done better to get the ADSLNation one http://www.adslnation.co.uk/products/xte2005.php

Eric

Have to agree.

BT Engineer attending to a fault wasn't impressed with my new Solwise Faceplate.
He replaced it [FOC] with a BT unit.

Thanks for the info guys, I think will order an ADSLNation one.

So how is the exchange line wired into the master socket?

In reply to:

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They're certainly supposed to be filtered, but the Solwise one is a bit cheap and nasty.

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Oh. I obviously made a mistake, and should have bought the ADSLNation one three or four years ago. Aren't I lucky that I have had no problems whatsoever in that time with this obviously completely inadequate piece of kit. I obviously should have spent the extra 5p rather than buy this cheap and nasty thing. (Of course there was a problem in that the the ADSLNation equivalent wasn't available then, so I suppose I should have done without until it arrived since it obviously shouldn't have worked as well as it did).

And if you haven't noticed, some of this is a joke. Some is also a criticism. Please try and work out which is which before you complain. I do happen to have used both items and neither I nor the other three installations I have made using it have had a problem with the Solwise faceplate. The only reason I prefer to use the ADSLNation offering is because it allows the unfiltered extension which would have been extremely useful on one of my installations, but they were unable to supply it. (Or if they were they couldn't be bothered to tell me which would not have been difficult since I was looking precisely for a faceplate with an unfiltered output).

I placed an order with ADSLNation today for a client's installation. The faceplate was the only thing they could provide from my list, the rest came from Solwise and would have included their faceplate except that this installation needs an unfiltered extension.

I'm not really sure what that rant was about, but I stand by my statement. Even cheap and nasty filters will be adequate in many situations, but better ones will work better, and in more situations. The Solwise faceplate uses a simpler and less precise filter circuit than the active filter used in the ADSLNation faceplate. I'm sorry if you have difficulty accepting this fact.

Eric

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I'm sorry if you have difficulty accepting this fact.

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Fact? I only see conjecture with no evidence. I suggest that there may be some situations where the ADSLNation faceplate works but the Solwise doesn't. I suggest that this is an inadequacy of the circuits on which it is being used and the solution would better be to solve the problems rather than use something which may be better at concealing the faults.

If you are being factual then you are saying that the Solwise filter does not mee the standards and specifications for its purpose. If that is the case, I suggest you have a duty to present the evidence to the appropriate Trading Standards Officer. Solwise claim that their filters have been tested by BT to the requirements of SIN346. Is this claim false? If it is true then how can they be described as inadequate?

I can accept it as a fact that Solwise are lying and engaged in commercial malpractice, but I need quite a lot of evidence to do so. You conjecture is neither fact nor evidence so I do not accept it as either.

Exactly where did I say that the Solwise filter doesn't meet the spec? By their very nature electronic filters vary in performance; you can meet the spec with a fairly simple filter (like the Solwise) but you can get better than that minimum performance with a superior filter (like the ADSLNation). We're not talking about absolutes here but shades of grey: many filters meet the spec, but some are better than others.

Eric

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many filters meet the spec, but some are better than others.

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A filter either meets the spec, in which case it meets it completely or it doesn't. The line on which they are to be used also has a spec. If it doesn't meet the spec the filter probably won't work. Some filters might work in that circumstance, but you now have two unknowns: the inadequacy of the line and the capability of the filter to perform outside it specified requirements. What indication is there that the filter will always work well with the inadequate line? Wouldn't it be better to deal with the problems in the line rather than try unspecified additional features of the filter which may or may not be up to dealing with unknown further inadequacy in the line?

If a filter meets the specification, it has completely met the specification. It is adequate to the task. Do you usually describe things which are correctly designed to fulfill the task for which they are designed as "nasty"? If you normally do use this word to describe the perfectly adequate then I agree that you did not accuse the Solwise filter of being below spec.

Hope the OP is following all this ok

I apologise to the OP for an element of sideline. It is very possible that the original filtered faceplate provided by Solwise was faulty, though there are other possible explanations of the symptoms. The suppliers should be prepared to provide a replacement which should then work. That is not quite the same situation as the suggestion that the filter was inherently inadequate (and the major problem detected here could hardly be explained by the marginal differences that might exist between different filters which meet the required standard to which the line itself is also expected to conform).

For those who have been following this little drama, I fitted an ADSLNation faceplate this morning and all is now well. The phone works fine without needing an intermediary filter.

So in summary, either the ADSLNation faceplate is 'better' in my circumstances than the solwise one or the solwise one I had was simply faulty. I am not really bothered either way, I am just happy that things are now working as they should.

Then we're all happy.

Eric

Except Solway? .....oh..and possibly junderwood

I think I'd rather trust actual experiences over theory anytime. As the front-page editorial on this web site says, ADSL filters which were OK for 1M and 2M broadband may not work well for ADSL Max and ADSL2+. If you visit the ADSL Nation website, they have a page showing the innards of some so-called "in spec" filters, and it's obvious that not all filters are the same.

Well yes, and the notion that an in-spec filter should always work with an in-spec line is naive to say the least. In fact I'm not at all sure that there is a spec for the ADSL quality of a telephone line, is there? If there is, it's certainly not guaranteed; the only guarantee is that the line is suitable for low frequency voice communication.

Eric

True and there are plenty of examples on here and that I have come across myself were two filters in series is required so the specification is obviously not enough sometimes, SKY boxes being particularly notorious. Basically all the spec for a filter states, from an interference POV, is that it should have certain levels of rejection of unwanted frequencies at certain frequencies. I believe it is 29db at 32KHz (upstream) and 55db between 300KHz and 1.1MHz (downstream) which I don't believe has changed since 512Kbps days. I have many old and some newish ones complete with CE mark that test within spec and are fine on fixed speed up to 2Mb but are rubbish on LLU or MAX even on internal wiring that is near perfect. While the basic specification is adequate in the majority of situations there are so many variables between different consumer home setups as regards what is connected as well as the range of telephone line conditions that it would be surprising if there weren't situations where a filter meeting the basic specification was inadequate out of the millions online.

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Well yes, and the notion that an in-spec filter should always work with an in-spec line is naive to say the least.

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What is the purpose of specifications other than to define what is required of a component in order ot work with other specified components?

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In fact I'm not at all sure that there is a spec for the ADSL quality of a telephone line, is there?

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Yes.

In reply to:

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If there is, it's certainly not guaranteed; the only guarantee is that the line is suitable for low frequency voice communication.

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Whether it is guarnateed depends on the provider who may guarantee that the product meets the specification. If the line fails to meet the specification then it could be the result of many factors, many of which are under the control of the owner of the line and the premises in which it resides. Nobody else can guarantee that those factors are not involved.

If the filter meets the requirements of the specification (which should be a guarantee by the supplier, if the individual item is faulty they should replace it, it it is designed wrongly the the commercial claim that it does meet the standard is fraudulent), then the failure for the line and the filter to work together is not the fault of the filter. That is all I have said on this subject.

It is possible that another filter may have been designed to its own standards, and may work with the faulty line. I contend that this is not a safe solution to a problem since it relies on the constant performance of an line working outside its specification and the unspecified additional features of a filter.

Please remember that the issue here was not whether the original, Solwise, filter as an individual component worked correctly, but the general statement that these filters were cheap and nasty. In view of the fact that Solwise claim that they meet the defined standard, such an accusation is defamatory. I am very happy that the OP obtained a result by replacing the filter. I am sorry that he had to pay an additional charge for this, since the probability is that a replacement of the original item would have worked just as well unless there was a serious problem with his line (i.e. all the bits of the line up to the point where the filter was attached, and that includes all extensions and other items of equipment on the line). If that is the case, it is of little concern to me but I am would not be happy in his position to rely on the solution being totally effective or long-term.

In reply to:

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True and there are plenty of examples on here and that I have come across myself were two filters in series is required so the specification is obviously not enough sometimes, SKY boxes being particularly notorious.

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Is it the specification that is at fault or the equipment placed on the line that causes it to be out of spec? Your mention of a notorious cause of bad lines rather suggests the latter.

Nothing has changed in the low-pass filter specification because of the higher frequencies used in current ADSL. The same low-pass band must be passed by the filter and nothing above is allowed through.

Of course there will be cases where a filter which is in-spec does not work in a particular situation. All that indicates is that the situation is out of spec. There are two ways of dealing with that - correct the problem or patch it up but modifying the associated equipment. I know which I believe to be the safe approach and am not at all happy that others leave the impression that a bodged job is acceptable.

And what is this ADSL line specification? There is a specification for ADSL equipment but there isn't one for the line beyond a line being suitable for voice and a 28Kbps modem. Additionally, you now have lines being provisioned for MAX that would often fail or be refused for fixed speed provisioning. On some of these lines where you might be getting a barely usable signal at the receive end even the 55db rejection of an in spec filter of any noise at relevant frequencies coming from the telephone side of the filter might not be enough to leave an usable signal. The only thing that could be considered out of spec is the line length, it's electrical condition and/or external noise. In such a situation I can't see BT replacing or improving such a length, all else being equal, unless it impinges on voice operation as there is no USO, i.e. minimum spec, for ADLS. I have had a number of such situations and a better specified filter such as an X1 has meant the difference between stable, unstable or even no ADSL, irrespective of what was plugged in on the voice side.

>> >> In fact I'm not at all sure that there is a spec for the ADSL quality of a telephone line, is there?

>> Yes.

Oh no there isn't.

The BT filter spec was defined several years ago, long before IPStream Max was in use in the UK. It was an attempt to define a filter which would work in most (if not all) circumstances, based on the knowledge available at the time. There's no ADSL line spec to match it up against, so there was never any certainty that it would always be adequate. With Max pushing the technology further out, there are now more situations where the minimum spec is not adequate. These situations require a better filter.

Eric

In reply to:

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These situations require a better filter.

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Which frequencies should not be filtered out which were not required to be filtered out in the past and at what level?

The standard for filters lets through what is required for the voice channel. What parts of that should be blocked now that ADSLMax has been introduced?

In reply to:

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And what is this ADSL line specification?

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You appear to be asking a specific question about a technical matter. I am prepared to answer that on a professional basis. I provided a complete answer to the original question that was asked.

I would like to add a few things to this thread about filters.

There are huge differences in the designs of filters, some have been known to claim they meet BT spec such as Tekhal that clearly do not. In the case of the Tekhal branded filter there was a wire that passed the ring signal from the line through the filter, an error that is specifically highlighted in the BT spec. So there are some companies out there that are making claims that are not correct. I don't know if this is deliberate or just they have assumed that all filters meet the standard so have put it in thier product description. In the case of Solwise they have sold two types of faceplate, one made by Austin Taylor and one by Pressac. It would seem that they have mostly run down their stock of the Austin Taylor one and have started supplying the Pressac version. The Pressac one was designed in association with BT to meet the spec and has been tested by BT exact labs to prove it meets the spec, so they are not misleading anyone by stating that for the faceplate. I would add however that their microfilters and extension sockets are very basic and I can not imagine they could get them through test, but I'm not in a position to know if they have been tested and passed by some mirical.

It is very common for people to find that filters that seemed to work fine with a fixed speed connection now need replacing with Max. The reason being that often with a fixed speed line your SNR margin would be high, say 20db. Using the phone might make it drop to 10db but that wouldn't cause a problem because you still have enough margin to maintain a connection at the speed required. However with ADSL Max the line syncs at the highest speed possible without letting the SNR margin drop below 6db. Now if you use your phone and you losse 2db of your margin your link is lost as the margin is not suitable for the speed you are connected at and the modem re-syncs. If you replace your filters with another model that does not couse a change in the SNR margin then you will not losse sync. Equally if you install better filters that boost the SNR margin available you will get fater speeds on Max.

Filter technology has evolved since the days when the Pressac faceplate was designed but it is still a very capable filter so it should work ok for most people.

Deleted

Edited by deleted (Mon 09-Oct-06 16:34:44)

As far as I know there are only two manufacturers of these 'High Quality' filters for use on a BT NTE5 master socket, Pressac and Austin Taylor. By 'High Quality' I mean they are based on a three stage coupled inductor design. In fact all filters will have thier own idiosyncracies and personally I prefer a single stage design with a less agressive high cut as this seems to be more Caller-ID friendly.

At Solwise we stock both manufacturers devices and based on test results we consider them to be interchangeable, though, probably as a result of misguided forum postings, our customers seem to have developed a preference for the Pressac one. This is the model with the curved top. The ADSLNation model looks like a re-badged Austin Taylor one, with a sloping top.

We sell about 600 of these units per month and have very few returns of either type, maybe 3 or 4 in the last 12 months, of course your unit could be one of the faulty ones.

Now, ADSL frequencies are inaudible. If you can hear 'static' on the line this can only be because the ADSL frequencies are being translated down into the audio band as a beat frequency caused by an interaction with another high frequency signal. Typical sources of such frequencies include cordless phones and anything with a switched mode power supply. Before condeming your filter it is worth switching off a few electrical devices which may be getting some radio-frequency energy on to the raw ADSL side of your line. Sometimes just moving your cordless phone base-station will get rid of the noise.

There is further coverage of these issues on the Solwise forum. I hope this rather wafly and over-technical posting will help some-one!

Thanks for that reasonable comment. The only thing I would add is that the ADSLNation faceplate uses an active filter with transistors, so I don't think that your guess at its identification is right. I've seen tests which suggest that active filters are not so good in plug-in units because they don't play well together when there's more than one, but that's not a problem with an NTE5 faceplate filter of course.

Eric

In reply to:

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I hope this rather wafly and over-technical posting will help some-one!

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It helped me, so thank-you. It restored my confidence in my own technical knowledge. I wish I had made the point about the noise frequency at the beginning, I certainly intended to but was distracted by the unwarranted condemnation of your product for which there is no evidence of incompetent or inadequate design, though faulty items may occur.

My contention has always been that a filter built within spec should not fail in normal circumstances. If a non-faulty filter built to the required specification is involved in a failure environment, there is a high probability that it is somethng on the line, not something in the filter which is the cause of the problem. In this case, as you point out, there is a certainty of a fault somewhere on the line. He reports audio frequency noise. If any ADSL filter were to remove that, it would be behaving well outside specification and not "better than" in any sense.

All I can say is that out of the half dozen or so filters I have tried, the solwise one was the only one which messed up my phone, I am glad that only 1 of 6 was 'in spec' (and there was no problem when connecting the phone directly without a filter, so doubt it is a simple line issue).

It was rhetorical but if I had thought that you had given a complete answer I wouldn't have replied.

You stated: "In fact I'm not at all sure that there is a spec for the ADSL quality of a telephone line,"

and then asked: "is there?"

Had the question been "What is it?" or something else seeking information about content, "Yes" would not have been adequate.

If you had asked if there were something called French Onion Soup, would you have expected the response "Yes" or a recipe? The former would have been a complete and accurate answer to the question, the latter might have been interesting additional information, but it wasn't asked for in the question. The responder might, just as easily, have assumed that anyone who would be able to make use of a recipe would know where to find it. I don't think that situation is far removed from this one.

I used to be Learned
I'm not sure what it meant but it made me feel good
I liked being Learned

Now I'm a Regular
I must have forgotten something
Being a Regular is fine

If this continues I may become a Newbie
I can't remember what that felt like
If I try hard I might remember and be Learned again

I liked being Learned
I said things and people listened
Perhaps they stopped listening, I don't know why

Edited by deleted (Tue 10-Oct-06 15:37:03)

Actually no I didn't, that is what roseway posted.

My post started with "And what is this ADSL line specification?...."

I was using a Solwise faceplate that I bought over 3 years ago when I first got ADSL, reading your post persuaded me to do a test. So I ordered a new faceplate from ADSL Nation and whilst I was there also got a new RJ11 lead using high quality twisted pair cable.

My line length is 3.2 km (according to Bt line tester), Interleaving is on, and although I can sync at 7968kbps and get onto a 7000kbps profile the line takes a bit of managing and babysitting. The main problem for me is losing sync overnight, I use the DMT tool to keep my router connected at the highest sync rate the line can manage.

One week ago I got the ADSL Nation faceplate and new cable. Result, around 3dB increase in SNR margin, and the router has stayed connected for one full week, no more overnight losses of sync. A very good result.

I did just briefly test with the faceplate and cable separately and the faceplate gave 2dB on its own, the cable 1dB. I wasn't interested in doing an overnight test like this. This might not sound very much, but when using the DMT tool to bring a target SNR down from 9dB to 6dB its quite significant and will make a big difference to line stability.

So whatever the arguments thanks for the suggestion, I for one am pleased to have changed and got a good result. I don't know whether the original faceplate was faulty or an old design, it doesn't matter why, the end justified the means in my case.