Is it possible to bypass a microfilter for an ADSL modem.

We have an extension in a spare bedroom which is currently connected to the
master bt socket by means of a plug and a 2-way splitter. I'd like to tidy
this up, and am thinking about wiring the extension directly into the master
bt socket (it's a socket with a removable bottom half).

If I go ahead and do this, I plan to use the socket in the bedroom for an
ADSL modem. I'd then use a microfilter in the master bt socket for the
telephone in the hallway.

If I go ahead and wire the extension into the master bt socket, the ADSL
modem wouldn't effectively be plugged into the main line and NOT via the
microfilter. My question is whether this would cause problems?

Thanks,
Wayne.

"wh" <(E-Mail Removed)> wrote in message
news:wnI0b.1403$(E-Mail Removed)...
> We have an extension in a spare bedroom which is currently connected to
the
> master bt socket by means of a plug and a 2-way splitter. I'd like to tidy
> this up, and am thinking about wiring the extension directly into the
master
> bt socket (it's a socket with a removable bottom half).
>
> If I go ahead and do this, I plan to use the socket in the bedroom for an
> ADSL modem. I'd then use a microfilter in the master bt socket for the
> telephone in the hallway.
>
> If I go ahead and wire the extension into the master bt socket, the ADSL
> modem wouldn't effectively be plugged into the main line and NOT via the
> microfilter. My question is whether this would cause problems?
>
> Thanks,
> Wayne.
>

My dad has his ADSL modem connected directly to his line. He used the two
supplied filters for his two existing telephones. The ADSL modem seems quite
happy without a filter on it.

Actually, does anyone know if the splitters actually do anything to the ADSL
side, or are they just wired straight through?

Dan.

On Wed, 20 Aug 2003 13:45:55 +0100, "Dan Wood"
<(E-Mail Removed)> wrote:

>Actually, does anyone know if the splitters actually do anything to the ADSL
>side, or are they just wired straight through?
>
Filters are for telephone related equipment, not for ADSL equipment.

Andrew.

Hi,
Have a look at this site http://www.adsl-filters.co.uk/tutorial.html
It sums up the options quite nicely.
Ray


"wh" <(E-Mail Removed)> wrote in message
news:wnI0b.1403$(E-Mail Removed)...
> We have an extension in a spare bedroom which is currently connected to
the
> master bt socket by means of a plug and a 2-way splitter. I'd like to tidy
> this up, and am thinking about wiring the extension directly into the
master
> bt socket (it's a socket with a removable bottom half).
>
> If I go ahead and do this, I plan to use the socket in the bedroom for an
> ADSL modem. I'd then use a microfilter in the master bt socket for the
> telephone in the hallway.
>
> If I go ahead and wire the extension into the master bt socket, the ADSL
> modem wouldn't effectively be plugged into the main line and NOT via the
> microfilter. My question is whether this would cause problems?
>
> Thanks,
> Wayne.
>
>

In article <(E-Mail Removed)>, aep@nospam writeme.com wrote:
> On Wed, 20 Aug 2003 13:45:55 +0100, "Dan Wood"
><(E-Mail Removed)> wrote:
>
>>Actually, does anyone know if the splitters actually do anything to the ADSL
>>side, or are they just wired straight through?
>>
> Filters are for telephone related equipment, not for ADSL equipment.
>
Not strictly true, depending on how you interpret what the filter is to do,
isolate the phone from the ADSL equipment or vice versa.

Some voice equipment is electrically noisy and will actually cause your ADSL
equipment to perform badly and sometimes prevent you from connecting at all!
A good example is those pesky Sky Box's. This is why a microfilter should
always exist between your ADSL equipment and voice equipment (including Faxes
and 56k modems). The splitters prevents any high frequencies (in the ADSL
range) from the spilling to the DSLAM and ADSL equipment; other things they
do is properly terminate your equipment to prevent reflections, if I remember
correctly. On the last bit I will wave the disclaimer permitting me to be
wrong though

I recommend that the splitter goes straight into the BT wall socket and from
there you ADSL modem/router plugs straight into it with no extension leads
what-so-ever. Then in the telephone socket on the splitter you can plug in
all your voice equipment needs.

Better still I would recommend you splash out £12 or so on an ADSL faceplate
and splitter combined. Available from a number of places, off the top of my
head http://solwise.co.uk/ Just remember, any extension leads to your ADSL
equipment is generally a Bad Idea (TM).....although it might work its not
optimal.

Regards

Alex

--
Alexander Clouter <(E-Mail Removed)>
MetroNet Support http://www.metronet.co.uk/support/

On Wed, 20 Aug 2003 16:51:16 +0100, Metronet Support
<(E-Mail Removed)> wrote:

>Some voice equipment is electrically noisy and will actually cause your ADSL
>equipment to perform badly and sometimes prevent you from connecting at all!

I thought all "wires only" ADSL modems came with a high pass filter on
their input for this reason, as there isn't the high pass / low pass
splitter on the replacement master socket.

Phil

On Wed, 20 Aug 2003 20:12:10 +0100, Metronet Support
<(E-Mail Removed)> wrote:

>Yes they do, however if your telephone equipment is 'noisy' in the high
>freqency regions, bear in mind they are rated for telephone usage, then there
>is nothing stopping this signal leaking to the DSLAM and/or ADSL equipment,
>as the high pass filter actually lets the signal through.

but the ADSL connection on a microfilter (according to the BT SIN) is
simply in parallel with the line conneciton, so how would putting a
"microfilter" between the ADSL modem and the already filtered noisy
phone help ?

Shirley the microfilter on the noisy phone is low pass and hence
blocks the alleged HF noise from the phone.

Phil

In article <di01ib.ed5.ln@127.0.0.1>, Metronet Support wrote:
> If a microfilter is placed at [z], for example just to rely on the
> microfilter (or an extra one) built into the ADSL kit, then the telephone
> cannot 'harm' the ADSL kit but the signals the ADSL kit sends to the DSLAM
> and and noise the telephone leaks to the DSLAM get mixed up,

Don't the signals from the telephone and the ADSL equipment have to be mixed
anyway, as they have to share the line?

Rod.

In article <(E-Mail Removed)>, Roderick Stewart wrote:
> In article <di01ib.ed5.ln@127.0.0.1>, Metronet Support wrote:
>> If a microfilter is placed at [z], for example just to rely on the
>> microfilter (or an extra one) built into the ADSL kit, then the telephone
>> cannot 'harm' the ADSL kit but the signals the ADSL kit sends to the DSLAM
>> and and noise the telephone leaks to the DSLAM get mixed up,
>
> Don't the signals from the telephone and the ADSL equipment have to be mixed
> anyway, as they have to share the line?
>
yes they do, but in your head you have to imagine there are two completely
seperate signals. The high frequency ones which belong to the ADSL side of
things and the low frequency ones which belong to the voice equipment.
Problems occur if two sets of high frequencies (both from the telephone and
adsl equipment) get mixed together. The flip side is you probably have heard
the 'hissing' noise when you do not use a microfilter; this is the ADSL
signal leaking into the voice part; not imagine it the other way round.

The microfilter, when properly placed, makes sure the high frequencies
leaving your house are _only_ from the ADSL kit whilst the low frequencies
_only_ are made from your voice equipment. If any leakage in either
direction occurs then bad things happen....witches, demons, and usually a
small furry animal (hampster) has to be sacrificed to appease the great
bandwidth God, Maximus-Downloadiness....

/me makes note to put extra extra clear instructions in his forthcoming
support system.....

Regards

Alex

--
Alexander Clouter <(E-Mail Removed)>
MetroNet Support http://www.metronet.co.uk/support/

On Thu, 21 Aug 2003 00:34:37 +0100, Metronet Support
<(E-Mail Removed)> wrote:

>From your question/statement its hard to work out if we are arguing the same
>point

I think you are saying that a crappy phone or sky box may put out HF
noise. As it should be connected through a microfilter (low pass
filter) this will be kept to the phone, just as the ADSL will be kept
out of the phone.

So far so good.

You seem then to suggest it may be a good idea to have a microfilter
on the ADSL modem which is where we disagree. For three reasons
a) ADSL modems for wires only already have a high pass filter built in
b) A high pass filter or microfilter will not reduce your HF noise
from telephone problem
c) Microfilter ADSL connections are wired parallel to the line and not
filtered at all.

So if I accept your notion of HF emitting phones/sky boxes I don't see
how using a microfilter (which in the case of its ADSL connection is a
non-filter) can help as any filtration is high pass and therefore does
not impact upon the alleged noise.

The only filter that can help is the low pass phone connection on the
noisy device.

Your witness.

Phil