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.