Two failed microfilters - does this indicate a line fault?

A customer with a BT router (not sure what model) has experienced permanent
loss of DSL carrier on two occasions. Each time when I've gone out, it's
been the microfilter that's been at fault: replacing the filter with a new
one restores perfect service. The two filters are different types.

Does this indicate a problem with the outside line or a problem with the
router? The customer says that she thinks the problems began when she
replaced a BT ADSL modem with the router. When I've investigated, neither
the router nor the modem will work. Could a line or router fault cause a
microfilter to fail?

As far as the customer is aware, there is only one socket off the incoming
line (thought it's not a BT master socket, which makes me suspicious!) and I
tried the original filter with no phones plugged in before trying a new
filter.

Martin Underwood wrote:

> A customer with a BT router (not sure what model) has experienced permanent
> loss of DSL carrier on two occasions. Each time when I've gone out, it's
> been the microfilter that's been at fault: replacing the filter with a new
> one restores perfect service. The two filters are different types.

Have you established the nature of the fault with the microfilters ?

Without that info anything would be a guess.

Graham

"Martin Underwood" <a@b> wrote in message
news:4623b23d$0$8726$(E-Mail Removed)...
>A customer with a BT router (not sure what model) has experienced permanent
> loss of DSL carrier on two occasions. Each time when I've gone out, it's
> been the microfilter that's been at fault: replacing the filter with a new
> one restores perfect service. The two filters are different types.
>
> Does this indicate a problem with the outside line or a problem with the
> router? The customer says that she thinks the problems began when she
> replaced a BT ADSL modem with the router. When I've investigated, neither
> the router nor the modem will work. Could a line or router fault cause a
> microfilter to fail?

Not very likely but the quality of a lot of microfilters is very poor.
Price is no guide to quality in my experience.
The BT ones that came with one of my routers were very badly tuned and you
couldn't use a modem plugged into the phone side.
The £1.99 ones I got from either CPC or ebuyer work perfectly.

Better still get a dedicated phone line if its for an office then you don't
need a microfilter at all.

I don't know what causes it but I think its just life. Same as when
there were internal dial up modems they would flake out now and again,
who knows why, power surges or something? External serial modems could
take it though and never died?

Anyway in my first two years of adsl I went through about five
microfilters, the ones that came with the speedtouch modem, one that
was bundled with my neighbours router and several different brands
from ebuyer.

In the end I just bought half a dozen of the cheapest microfilters
for 99p each from ebuyer and I reckon they will last me several
years. I think thats the answer in the end.

Of everything that could get fried I'd rather it was the 99p filter
to be honest.

Eeyore wrote in message
(E-Mail Removed):

> Martin Underwood wrote:
>
>> A customer with a BT router (not sure what model) has experienced
>> permanent loss of DSL carrier on two occasions. Each time when I've
>> gone out, it's been the microfilter that's been at fault: replacing
>> the filter with a new one restores perfect service. The two filters
>> are different types.
>
> Have you established the nature of the fault with the microfilters ?
>
> Without that info anything would be a guess.

How do I test a microfilter to find out what the fault is. Should I measure
the voltage across certain pins on the lead that plugs into the router, when
that lead is plugged into the suspect filter and thence into the phone line?

All I can say is that a router which used to work with one filter no longer
does, and if that filter is changed (with the same phone line and the same
filter-router cable) the router works again. Unfortunately neither the
router nor the modem have the ability to report noise margin and
attentuation.

I had an unauthorised phone in my bathroom. The microfilters there have
failed twice. I blame my partner's bathroom habits...

I have a BT hub.

All seems to work well despite the exposed connection box outside...

--
Helen D. Vecht: (E-Mail Removed)
Edgware.

Is it an underground or overhead line.
If overhead, the lightning in the area can do it.

Alec



"Martin Underwood" <a@b> wrote in message
news:4623b23d$0$8726$(E-Mail Removed)...
>A customer with a BT router (not sure what model) has experienced permanent
> loss of DSL carrier on two occasions. Each time when I've gone out, it's
> been the microfilter that's been at fault: replacing the filter with a new
> one restores perfect service. The two filters are different types.
>
> Does this indicate a problem with the outside line or a problem with the
> router? The customer says that she thinks the problems began when she
> replaced a BT ADSL modem with the router. When I've investigated, neither
> the router nor the modem will work. Could a line or router fault cause a
> microfilter to fail?
>
> As far as the customer is aware, there is only one socket off the incoming
> line (thought it's not a BT master socket, which makes me suspicious!) and
> I
> tried the original filter with no phones plugged in before trying a new
> filter.
>

Is it an underground or overhead line.
If overhead, the lightning in the area can do it.

Alec



"Martin Underwood" <a@b> wrote in message
news:4623b23d$0$8726$(E-Mail Removed)...
>A customer with a BT router (not sure what model) has experienced permanent
> loss of DSL carrier on two occasions. Each time when I've gone out, it's
> been the microfilter that's been at fault: replacing the filter with a new
> one restores perfect service. The two filters are different types.
>
> Does this indicate a problem with the outside line or a problem with the
> router? The customer says that she thinks the problems began when she
> replaced a BT ADSL modem with the router. When I've investigated, neither
> the router nor the modem will work. Could a line or router fault cause a
> microfilter to fail?
>
> As far as the customer is aware, there is only one socket off the incoming
> line (thought it's not a BT master socket, which makes me suspicious!) and
> I
> tried the original filter with no phones plugged in before trying a new
> filter.
>

On Mon, 16 Apr 2007 20:14:55 +0100 Martin Underwood
from the village of a@b
felt we might be interested in the following...


> How do I test a microfilter to find out what the fault is.

How much do you charge an hour? How much does a new filter cost?

> All I can say is that a router which used to work with one filter no longer
> does, and if that filter is changed (with the same phone line and the same
> filter-router cable) the router works again. Unfortunately neither the
> router nor the modem have the ability to report noise margin and
> attentuation.

I refer the gentleman to the question i posed earlier.

Much as you'd undoubtedly like to know the answer, is it worth your time
to find out?

Bung a new filter on there - it works - leave site.

--
My reply address is valid, but incoming mail is set to 'auto-delete'
so will not be seen. Please post replies to the group.
XPS M1710 / 2.16 GHz dual core / 2Gb DDR2 / nVidia GeForce 7950GTX

Tx2 wrote in message
(E-Mail Removed):

> On Mon, 16 Apr 2007 20:14:55 +0100 Martin Underwood
> from the village of a@b
> felt we might be interested in the following...
>
>
>> How do I test a microfilter to find out what the fault is.
>
> How much do you charge an hour? How much does a new filter cost?
>
>> All I can say is that a router which used to work with one filter no
>> longer does, and if that filter is changed (with the same phone line
>> and the same filter-router cable) the router works again.
>> Unfortunately neither the router nor the modem have the ability to
>> report noise margin and attentuation.
>
> I refer the gentleman to the question i posed earlier.
>
> Much as you'd undoubtedly like to know the answer, is it worth your
> time to find out?
>
> Bung a new filter on there - it works - leave site.

Exactly. Much cheaper for the customer if I simply replace the filter.

I only asked how you tested a filter because Eeyore seemed to think that I
should have done so in order that he could diagnose the problem. I was
curious as to the tests that he thought I should have carried out.

I think the phone line is underground rather than from a pole, so lightning
strikes are less likely.

Are there any components in a microfilter between the line connection and
the DSL socket to the router, or is it a straight-through connection? I
thought it was only the phone socket that had filter components on a signal
that is tee'd off the input to the filter.