Microfilters - I can still hear a faint noise in the background

Perhaps somebody could just confirm that what is happening on my phone line
is normal.

Our telephone line has just been adsl enabled so I've purchased a Fujitsu
FDX100-UK microfilter from:

http://www.adsl-filters.co.uk/index.html

Although it's plugged in I still hear a noise in the background. It's not as
strong as it is when the microfilter is *not* plugged in but then again it's
not as quiet as before our line was enabled. If it helps, I can only hear
the noise when I've made a connection to our ISP.

Thanks,
Wayne.

"wh" <(E-Mail Removed)> wrote in message

> Our telephone line has just been adsl enabled so I've purchased a Fujitsu
> FDX100-UK microfilter from:
>
> http://www.adsl-filters.co.uk/index.html

The fuji is a good filter. The only thing I can think to suggest is try the
adslnation one instead.

http://www.adslnation.com/support/filters.php

Jc.

On Fri, 5 Dec 2003, Josey wrote:

J>
J> "wh" <(E-Mail Removed)> wrote in message
J>
J> > Our telephone line has just been adsl enabled so I've purchased a Fujitsu
J> > FDX100-UK microfilter from:
J> >
J> > http://www.adsl-filters.co.uk/index.html
J>
J> The fuji is a good filter. The only thing I can think to suggest is try the
J> adslnation one instead.
J>
J> http://www.adslnation.com/support/filters.php
J>

I have both of these filters in series on the answerering machine. This
reduced the noise so we can just about hear the messages.

Alan

( If replying by mail, please note that all "sardines" are canned.
There is also a password autoresponder but, unless this a very
old message, a "tuna" will swim right through. )

On Fri, 5 Dec 2003 11:04:05 -0000, "wh" <(E-Mail Removed)>
wrote:

>Perhaps somebody could just confirm that what is happening on my phone line
>is normal.
>
>Our telephone line has just been adsl enabled so I've purchased a Fujitsu
>FDX100-UK microfilter from:
>
>http://www.adsl-filters.co.uk/index.html
>
>Although it's plugged in I still hear a noise in the background. It's not as
>strong as it is when the microfilter is *not* plugged in but then again it's
>not as quiet as before our line was enabled. If it helps, I can only hear
>the noise when I've made a connection to our ISP.
>
>Thanks,
>Wayne.
>

I was just about to ask the same question! I have fitted the adsl
nation XF-1e filter which I believe is one of the best filters you can
get, but I still hear noise on the line when my PCI modem is powered.
Is it generally the case that none of these filters remove all of the
ADSL noise from the line.

Bryce

--
Bryce Whiteford
(E-Mail Removed)

"Bryce Whiteford" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> I was just about to ask the same question! I have fitted the adsl
> nation XF-1e filter which I believe is one of the best filters you can
> get, but I still hear noise on the line when my PCI modem is powered.
> Is it generally the case that none of these filters remove all of the
> ADSL noise from the line.

Normally in my experience, the noise goes if using a "quality" filter (I use
the official BT master socket).

Two reasons it may not:

1. A faulty filter
2. "Poor" telecommunications equipment (not always "cheap") - while they
work fine with voice calls, they have some difficulty with even a filtered
line.

Regards
Sunil

On Sat, 6 Dec 2003 11:32:05 -0000, "Sunil Sood"
<(E-Mail Removed)> wrote:

>
>"Bryce Whiteford" <(E-Mail Removed)> wrote in message
>news:(E-Mail Removed).. .
>> I was just about to ask the same question! I have fitted the adsl
>> nation XF-1e filter which I believe is one of the best filters you can
>> get, but I still hear noise on the line when my PCI modem is powered.
>> Is it generally the case that none of these filters remove all of the
>> ADSL noise from the line.
>
>Normally in my experience, the noise goes if using a "quality" filter (I use
>the official BT master socket).
>
>Two reasons it may not:
>
>1. A faulty filter
>2. "Poor" telecommunications equipment (not always "cheap") - while they
>work fine with voice calls, they have some difficulty with even a filtered
>line.
>
>Regards
>Sunil
>
I did some experimenting following your post and found that the
problem was caused by a phone that was plugged into an extension
socket. I had not fitted a filter to this phone yet as I do not
normally use the phone, it is really just used as an extension bell.
When I disconnected this phone, the noise that was present on my
filtered phone disappeared. So it looks as though the extension phone
was somehow allowing the ADSL noise to by-pass the filter (perhaps via
the ring circuit?). I had thought filters only needed to be fitted to
phones/modems etc that were actually passing speech or data to the
exchange.

I have more filters on order, but just wondering why this happens?


--
Bryce Whiteford
(E-Mail Removed)

Bryce Whiteford wrote:
>
> I did some experimenting following your post and found that the
> problem was caused by a phone that was plugged into an extension
> socket. I had not fitted a filter to this phone yet as I do not
> normally use the phone, it is really just used as an extension bell.
> When I disconnected this phone, the noise that was present on my
> filtered phone disappeared. So it looks as though the extension phone
> was somehow allowing the ADSL noise to by-pass the filter (perhaps via
> the ring circuit?). I had thought filters only needed to be fitted to
> phones/modems etc that were actually passing speech or data to the
> exchange.
>
> I have more filters on order, but just wondering why this happens?
>
>

You have to filter all devices attached to the phone line, except the
ADSL modem.

Bryce Whiteford <(E-Mail Removed)> wrote:

> I did some experimenting following your post and found that the
> problem was caused by a phone that was plugged into an extension
> socket. I had not fitted a filter to this phone yet as I do not
> normally use the phone, it is really just used as an extension bell.
> When I disconnected this phone, the noise that was present on my
> filtered phone disappeared. So it looks as though the extension phone
> was somehow allowing the ADSL noise to by-pass the filter (perhaps via
> the ring circuit?). I had thought filters only needed to be fitted to
> phones/modems etc that were actually passing speech or data to the
> exchange.
>
> I have more filters on order, but just wondering why this happens?

As I understand it, all phones on the line need a filter, whether they
are off-hook or not.

--
Alec McKenzie
(E-Mail Removed)

"Bryce Whiteford" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> I had thought filters only needed to be fitted to
> phones/modems etc that were actually passing speech or data to the
> exchange.

As the others have said, all the telephones/sky boxes/alarms need to be
filtered apart from the modem - regardless of whether you actively use them
or not.

Regards
Sunil

On Sun, 14 Dec 2003 11:29:39 +0000, in article
<(E-Mail Removed)> Bryce Whiteford
<(E-Mail Removed)> wrote:

> I did some experimenting following your post and found that the
> problem was caused by a phone that was plugged into an extension
> socket. I had not fitted a filter to this phone yet as I do not
> normally use the phone, it is really just used as an extension bell.
> When I disconnected this phone, the noise that was present on my
> filtered phone disappeared. So it looks as though the extension phone
> was somehow allowing the ADSL noise to by-pass the filter (perhaps via
> the ring circuit?). I had thought filters only needed to be fitted to
> phones/modems etc that were actually passing speech or data to the
> exchange.

It is likely that the unfiltered phone is being exposed to the ADSL
signals and is then remodulating a modified version of these signals into
the POTS frequency band, this is because the phone itself is simply not
designed to cope with these signals on its line interface.

All sorts of nasty non-linear devices in a phone to cause intermodulation
and mixing products to be generated.

--

Brian Morrison

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