Smart dialer causes phone line crackles now we have ADSL

For many years I've been using a "smart dialer" programmed to dial "140"
automatically before most calls so that they route through SkyTalk.

As we have line rental from BT and get around £5/quarter of free
local/national calls, to use this allowance every now and then we press
"##" to bypass the smart dialer and route through BT.

Fine, but 1 August we got ADSL broadband. The router works a treat but the
phone quality is degraded (slight crackling always heard) if the smart
dialer is connected to the "phone micro filter/adsl splitter":

BT master socket -> adsl micro filter -> smart dialer -> phones

1) Perhaps a more expensive microfilter would solve the problem? This is the
route I'll probably try next - I just got a 99p microfilter when I ordered
my ASR8400 from Ebuyer.

2) If I get carrier pre select on Skytalk, can I bypass it by a keypad
sequence to route a few calls through BT?

I used the search on the BT website for "carrier pre select" but they know
nothing about it.

--
Paul

On Sun, 10 Aug 2003 20:22:12 +0100 and in article
<(E-Mail Removed)>, Paul said...
: For many years I've been using a "smart dialer" programmed to dial "140"
: automatically before most calls so that they route through SkyTalk.
:
: As we have line rental from BT and get around £5/quarter of free
: local/national calls, to use this allowance every now and then we press
: "##" to bypass the smart dialer and route through BT.
:
: Fine, but 1 August we got ADSL broadband. The router works a treat but the
: phone quality is degraded (slight crackling always heard) if the smart
: dialer is connected to the "phone micro filter/adsl splitter":
:
: BT master socket -> adsl micro filter -> smart dialer -> phones
:
: 1) Perhaps a more expensive microfilter would solve the problem?

http://www.adslnation.com/products/xf-1e.php

Is your best bet.

--
CB

"Paul" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> 2) If I get carrier pre select on Skytalk, can I bypass it by a keypad
> sequence to route a few calls through BT?

Yes, you can prefix telephone numbers with "1280" to route calls via BT
if you use CPS with another company.

Regards
Sunil

CB wrote:

> : 1) Perhaps a more expensive microfilter would solve the problem?
>
> http://www.adslnation.com/products/xf-1e.php
>
> Is your best bet.

Thanks, I see that one gets 5 stars on their "Inside Microfilters" page

--
Paul

On Sun, 10 Aug 2003, Paul wrote:

P> CB wrote:
P>
P> > : 1) Perhaps a more expensive microfilter would solve the problem?
P> >
P> > http://www.adslnation.com/products/xf-1e.php
P> >
P> > Is your best bet.
P>
P> Thanks, I see that one gets 5 stars on their "Inside Microfilters" page
P>
P>

I have hum. The answering machine is unusable. We tried a new answering
machine and the incoming messages are still drowned by hum.

I was recommended to buy a more expensive microfilter so I bought the
Fujitsu standards compliant one and put that between the answering
machine and the line. But it doesn't cut out the hum.

Router is a Vigor 2600We.

Any thoughts anyone?

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. )

Alan Clifford wrote:
> On Sun, 10 Aug 2003, Paul wrote:
>
> P> CB wrote:
> P>
> P> > : 1) Perhaps a more expensive microfilter would solve the problem?
> P> >
> P> > http://www.adslnation.com/products/xf-1e.php
> P> >
> P> > Is your best bet.
> P>
> P> Thanks, I see that one gets 5 stars on their "Inside Microfilters" page
> P>
> P>
>
> I have hum. The answering machine is unusable. We tried a new answering
> machine and the incoming messages are still drowned by hum.
>
> I was recommended to buy a more expensive microfilter so I bought the
> Fujitsu standards compliant one and put that between the answering
> machine and the line. But it doesn't cut out the hum.
>
> Router is a Vigor 2600We.
>
> Any thoughts anyone?
>
> 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. )
>

mains hum

On Mon, 11 Aug 2003, Mark&Lisa wrote:

M> >
M> > I have hum. The answering machine is unusable. We tried a new answering
M> > machine and the incoming messages are still drowned by hum.
M> >
M> > I was recommended to buy a more expensive microfilter so I bought the
M> > Fujitsu standards compliant one and put that between the answering
M> > machine and the line. But it doesn't cut out the hum.
M> >

M>
M> mains hum
M>
M>

Hi, that thought did occur to me but I don't know how to deal with it. I
just know the words. Maybe I should try the router and answer phone in
the same electrical socket?

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. )

Alan Clifford wrote:

> M> mains hum
>
> Hi, that thought did occur to me but I don't know how to deal with it. I
> just know the words. Maybe I should try the router and answer phone in
> the same electrical socket?

That rang a bell.

I remember trying to record using a cable from my PC sound card into the
"mic" socket of a radio/cassette.

I had a double wall socket, in one side I had a 4-way running the PC/monitor
etc, in the other side the radio/cassete: result HUM

When I powered the radio/cassette from the 4-way: result NO HUM

I hope you've solved it.

--
Paul

"Alan Clifford" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) lifford.ac...
> On Mon, 11 Aug 2003, Mark&Lisa wrote:
>
> M> >
> M> > I have hum. The answering machine is unusable. We tried a new
answering
> M> > machine and the incoming messages are still drowned by hum.
> M> >
> M> > I was recommended to buy a more expensive microfilter so I bought the
> M> > Fujitsu standards compliant one and put that between the answering
> M> > machine and the line. But it doesn't cut out the hum.
> M> >
>
> M>
> M> mains hum
> M>
> M>
>
> Hi, that thought did occur to me but I don't know how to deal with it. I
> just know the words. Maybe I should try the router and answer phone in
> the same electrical socket?

There's a common problem called an "earth loop". If a signal cable with an
earthed shield connects two earthed appliances, there is an effective loop
formed by the two power cords, the appliances and the signal cable. Any
changing magnetic field passing through that loop will induce unwanted
currents in the signal cable, typically "hum".

Solutions are:

1. Twist the cables together and plug both appliances from the same socket
to reduce the area of the "loop".

2. Move the loop as far as possible from transformers and other mains
wiring.

3. Add isolating transformers to the signal cable. These are cheap, but you
need to know the impedances and signal levels involved and be handy with a
soldering iron. You need a capacitor as well if there is DC on the cable,
which microphone inputs sometimes have (to power the condenser amplifier).

4. Disconnect one of the earth connections. This is DANGEROUS so is not
really a practical solution, but it can help to prove the cause of the
problem if you know what you're doing.

--
Phil McKerracher
www.mckerracher.org