broadband filters

Having just put broadband in 2 days ago I am puzzled as to why I need
filters. I have just tried making and receiving phone calls with an
unfiltered telephone while on the interenet and had no interfernce,
crackling or whatever. I have 5 telephones in the house and filters are on 3
of them but the other 2 work just as well.
Does one need filters to lessen interference with the connection speed of
the computer?
Thank you.

"Stewart" <(E-Mail Removed)> wrote in message
news:cgptjd$3r6$(E-Mail Removed)...
> Having just put broadband in 2 days ago I am puzzled as to why I need
> filters. I have just tried making and receiving phone calls with an
> unfiltered telephone while on the interenet and had no interfernce,
> crackling or whatever. I have 5 telephones in the house and filters are on 3
> of them but the other 2 work just as well.
> Does one need filters to lessen interference with the connection speed of
> the computer?

Could it be that the 2 without filters are being filtered anyway via extension
lines?

My home telephone system is on a ring and the broadband modem is fitted via
a filter (I am now wondereing if this is the only one required) on the ring;
it is not next to the incoming bt main line.

"Beck" <(E-Mail Removed)> wrote in message
news:cgpuac$qe5$(E-Mail Removed)...
>
> "Stewart" <(E-Mail Removed)> wrote in message
> news:cgptjd$3r6$(E-Mail Removed)...
> > Having just put broadband in 2 days ago I am puzzled as to why I need
> > filters. I have just tried making and receiving phone calls with an
> > unfiltered telephone while on the interenet and had no interfernce,
> > crackling or whatever. I have 5 telephones in the house and filters are
on 3
> > of them but the other 2 work just as well.
> > Does one need filters to lessen interference with the connection speed
of
> > the computer?
>
> Could it be that the 2 without filters are being filtered anyway via
extension
> lines?
>
>

"Stewart" <(E-Mail Removed)> wrote in message
news:cgpuo9$9be$(E-Mail Removed)...
> My home telephone system is on a ring and the broadband modem is fitted via
> a filter (I am now wondereing if this is the only one required) on the ring;
> it is not next to the incoming bt main line.

I don't know, but if it works fine, then no problems. Something is obviously
filtering the two phones so all is well :-)

Have tried some more and now found that 2 of the phones interfere with the
broadband modem, do not know if they are nearer or further from the incoming
line than the broadband modem, any way it is working.

"Beck" <(E-Mail Removed)> wrote in message
news:cgpv5n$vn$(E-Mail Removed)...
>
> "Stewart" <(E-Mail Removed)> wrote in message
> news:cgpuo9$9be$(E-Mail Removed)...
> > My home telephone system is on a ring and the broadband modem is fitted
via
> > a filter (I am now wondereing if this is the only one required) on the
ring;
> > it is not next to the incoming bt main line.
>
> I don't know, but if it works fine, then no problems. Something is
obviously
> filtering the two phones so all is well :-)
>
>

You do not need a filter on the modem ADSL line but you do need it on all
the phones and telephone equipment like a FAX.

Otherwise when they use the phone it may disconnect the ADSL, well that's
what happens here.


"Stewart" <(E-Mail Removed)> wrote in message
news:cgq047$3s5$(E-Mail Removed)...
> Have tried some more and now found that 2 of the phones interfere with the
> broadband modem, do not know if they are nearer or further from the
incoming
> line than the broadband modem, any way it is working.
>
> "Beck" <(E-Mail Removed)> wrote in message
> news:cgpv5n$vn$(E-Mail Removed)...
> >
> > "Stewart" <(E-Mail Removed)> wrote in message
> > news:cgpuo9$9be$(E-Mail Removed)...
> > > My home telephone system is on a ring and the broadband modem is
fitted
> via
> > > a filter (I am now wondereing if this is the only one required) on the
> ring;
> > > it is not next to the incoming bt main line.
> >
> > I don't know, but if it works fine, then no problems. Something is
> obviously
> > filtering the two phones so all is well :-)
> >
> >
>
>

On Sat, 28 Aug 2004 14:10:22 +0100, "Stewart" <(E-Mail Removed)>
wrote:

>Have tried some more and now found that 2 of the phones interfere with the
>broadband modem

they may be ones that give out interference or react to the broadband
signal, that's why you're supposed to filter them :-)

Phil
--
spamcop.net address commissioned 18/06/04
Come on down !

If I read the wanadoo instructions correctly then they say that the
broadband modem has to be connected to the phone line via a filter, I have
done this and the computer works OK.



"It's Me" <(E-Mail Removed)> wrote in message
news:cgq4dc$5p8$(E-Mail Removed)...
> You do not need a filter on the modem ADSL line but you do need it on all
> the phones and telephone equipment like a FAX.
>
> Otherwise when they use the phone it may disconnect the ADSL, well that's
> what happens here.
>
>
> "Stewart" <(E-Mail Removed)> wrote in message
> news:cgq047$3s5$(E-Mail Removed)...
> > Have tried some more and now found that 2 of the phones interfere with
the
> > broadband modem, do not know if they are nearer or further from the
> incoming
> > line than the broadband modem, any way it is working.
> >
> > "Beck" <(E-Mail Removed)> wrote in message
> > news:cgpv5n$vn$(E-Mail Removed)...
> > >
> > > "Stewart" <(E-Mail Removed)> wrote in message
> > > news:cgpuo9$9be$(E-Mail Removed)...
> > > > My home telephone system is on a ring and the broadband modem is
> fitted
> > via
> > > > a filter (I am now wondereing if this is the only one required) on
the
> > ring;
> > > > it is not next to the incoming bt main line.
> > >
> > > I don't know, but if it works fine, then no problems. Something is
> > obviously
> > > filtering the two phones so all is well :-)
> > >
> > >
> >
> >
>
>

On Sat, 28 Aug 2004 17:02:05 +0100, Stewart wrote:

> If I read the wanadoo instructions correctly then they say that the
> broadband modem has to be connected to the phone line via a filter, I have
> done this and the computer works OK.

Only because microfilters have the correct socket on them to connect the
modem to, its rj11 and wont fit a BT type socket, thats all they mean. The
rj11 socket is a straight through connection in the filter ie is connected
direct to the phone line pair.

Dave
--

Some people use windows, others have a life.

On Sat, 28 Aug 2004 17:02:05 +0100, "Stewart" <(E-Mail Removed)>
wrote:

>If I read the wanadoo instructions correctly then they say that the
>broadband modem has to be connected to the phone line via a filter, I have
>done this and the computer works OK.
>
>
Perhaps a simple way to view the filters is to understand what they
are doing. The filters incorporate a 'high frequency output' and a
'low frequency output' where each output is isolated from the other
but both connect to the input (i.e. Phone line).

You need the modem to be connected 'directly' to the phone line, all
the way back to the incoming phone line. This is the same as plugging
it into the 'high frequency output' socket. You don't need the filter
at this point but it does give the correct connector for most modems
and should have minimal loss.

If you connect a phone (low frequency) across the line it will
effectively short the line at the higher frequencies and may stop the
signals to the modem. You therefore need to fit a filter between the
phone and the line to isolate it's effect on the 'high frequencies'.
This is what the filter achieves.

If you have sufficient signal levels on your phone line the modem may
well work but the filters guarantee there is isolation. Some phones
may well be affected by the higher frequencies from the modem and
cause interference, so again the filter isolates this effect.

If you view with fixed pitch font below you will see that S=Socket,
F=filter required and P=Phone. It doesn't matter if you have it wired
as a ring as the line and modem simply join up at both ends. For
convenience and improved isolation X(F)= filter preferred.

Phone Line ------------S-----------S------------S----------X(F) Modem
| | |
F F F
| | |
P P P

Hopefully that helps.