ADSL Filters: what's the difference?

Out of idle curiosity I decided to open up a couple of spare filters to
see what's in them. Not much! They are two different types; one has a
lead to the wall socket and is about and inch by and inch-and-a-half
square. The other plugs directly into the wall socket and is smaller.

When I opened them up I found that the larger filter has more capacitors
and resistors and stuff inside than the smaller one. It also has four
contacts on the RJ11 socket whereas the smaller one only has two, but
both have only two wires from the BT connector to the circuit board.

I've attached a photo here:

http://i122.photobucket.com/albums/o...9/DSC00621.jpg

What's the difference?

--
Abo

In message <fenocj$5pj$(E-Mail Removed)>, Abo <(E-Mail Removed)> wrote
>Out of idle curiosity I decided to open up a couple of spare filters to
>see what's in them. Not much! They are two different types; one has a
>lead to the wall socket and is about and inch by and inch-and-a-half
>square. The other plugs directly into the wall socket and is smaller.
>
>When I opened them up I found that the larger filter has more
>capacitors and resistors and stuff inside than the smaller one. It also
>has four contacts on the RJ11 socket whereas the smaller one only has
>two, but both have only two wires from the BT connector to the circuit
>board.
>
>I've attached a photo here:
>
>http://i122.photobucket.com/albums/o...9/DSC00621.jpg
>
>What's the difference?
>

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

--
Alan
news2006 {at} amac {dot} f2s {dot} com

Alan wrote:
> In message <fenocj$5pj$(E-Mail Removed)>, Abo <(E-Mail Removed)> wrote
>> Out of idle curiosity I decided to open up a couple of spare filters
>> to see what's in them. Not much! They are two different types; one has
>> a lead to the wall socket and is about and inch by and inch-and-a-half
>> square. The other plugs directly into the wall socket and is smaller.
>>
>> When I opened them up I found that the larger filter has more
>> capacitors and resistors and stuff inside than the smaller one. It
>> also has four contacts on the RJ11 socket whereas the smaller one only
>> has two, but both have only two wires from the BT connector to the
>> circuit board.
>>
>> I've attached a photo here:
>>
>> http://i122.photobucket.com/albums/o...9/DSC00621.jpg
>>
>> What's the difference?
>>
>
> See
> http://www.adslnation.com/support/filters.php
>

I see: 'the extra components are used to refine the frequency separation'

--
Abo

Abo wrote:
> Out of idle curiosity I decided to open up a couple of spare filters to
> see what's in them. Not much! They are two different types; one has a
> lead to the wall socket and is about and inch by and inch-and-a-half
> square. The other plugs directly into the wall socket and is smaller.
>
> When I opened them up I found that the larger filter has more capacitors
> and resistors and stuff inside than the smaller one. It also has four
> contacts on the RJ11 socket whereas the smaller one only has two, but
> both have only two wires from the BT connector to the circuit board.
>
> I've attached a photo here:
>
> http://i122.photobucket.com/albums/o...9/DSC00621.jpg
>
> What's the difference?
>

Several differences.

1) Cost!!
2) The cheap one doesnt have it's own 'ring capacitor' in it and the two
wires to the master socket don't even extend the 'ring wire' from the
master socket. As a result some phones wont ring (as I discovered at
friends)
3) The expensive one has filters in both the phone and ADSL side. This
isolates the ADSL completely from the phone being picked up etc and
provides proper terminations to each filter so they work well.

Mike

You pays your money and you gets your choice - more expensive is usually
better.

"Abo" <(E-Mail Removed)> wrote in message
news:fenocj$5pj$(E-Mail Removed)...
> Out of idle curiosity I decided to open up a couple of spare filters to
> see what's in them. Not much! They are two different types; one has a lead
> to the wall socket and is about and inch by and inch-and-a-half square.
> The other plugs directly into the wall socket and is smaller.
>
> When I opened them up I found that the larger filter has more capacitors
> and resistors and stuff inside than the smaller one. It also has four
> contacts on the RJ11 socket whereas the smaller one only has two, but both
> have only two wires from the BT connector to the circuit board.
>
> I've attached a photo here:
>
> http://i122.photobucket.com/albums/o...9/DSC00621.jpg
>
> What's the difference?

Are you quite sure that the outer two connections on the RJ11 socket
actually go anywhere useful on the PCB?

--
Graham.
%Profound_observation%

Abo, in article <fenvh9$jop$(E-Mail Removed)>, says...
>
>I see: 'the extra components are used to refine the frequency separation'

That's the marketing answer :-)

The more "poles" added to a filter, the steeper is its roll-
off (=the slope is steeper). This means the filter with a
greater (passive) component count is generally a better
choice, since the undesired frequency is attenuated more.

The one you have with one L and one C reduce the unwanted
signal by half for each doubling of frequency beyond the cut-
off point. An extra L makes it twice as good, etc...

--
JohnW.
Replace the obvious with co.uk in 2 places to mail me.

Graham. wrote:
> "Abo" <(E-Mail Removed)> wrote in message
> news:fenocj$5pj$(E-Mail Removed)...
>> Out of idle curiosity I decided to open up a couple of spare filters to
>> see what's in them. Not much! They are two different types; one has a lead
>> to the wall socket and is about and inch by and inch-and-a-half square.
>> The other plugs directly into the wall socket and is smaller.
>>
>> When I opened them up I found that the larger filter has more capacitors
>> and resistors and stuff inside than the smaller one. It also has four
>> contacts on the RJ11 socket whereas the smaller one only has two, but both
>> have only two wires from the BT connector to the circuit board.
>>
>> I've attached a photo here:
>>
>> http://i122.photobucket.com/albums/o...9/DSC00621.jpg
>>
>> What's the difference?
>
> Are you quite sure that the outer two connections on the RJ11 socket
> actually go anywhere useful on the PCB?
>
Hmm lets have a look! <pulls PCB out completely> Nope, they're just
soldered to 'spare' holes on the board, no tracks from them...

--
Abo

"Abo" <(E-Mail Removed)> wrote in message
news:fenvh9$jop$(E-Mail Removed)...

>> See
>> http://www.adslnation.com/support/filters.php
>>
>
> I see: 'the extra components are used to refine the frequency separation'
>

To a large extent that's just marketing speak.

However that filter (the XF-1e) is an excellent filter while your other
filter looks like it's probably rubbish.

Problems with poor filters include:

1. ADSL signals entering modern phone often cause a background hissing
noise.

2. Using the telephone can cause disruption to the ADSL signals causing
dropped connections or with MaxADSL lower speeds that would be possible with
good filters.

3. ADSL signals reaching a phone with caller ID display while it's not in
use can stop the calling number displaying properly.

--

Brian Gregory. (In the UK)
(E-Mail Removed)
To email me remove the letter vee.

"Mike J" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> 3) The expensive one has filters in both the phone and ADSL side.

No, actually it doesn't. The ADSL connection is still just a straight
through connection.

--

Brian Gregory. (In the UK)
(E-Mail Removed)
To email me remove the letter vee.

Brian Gregory [UK] wrote:
> "Abo" <(E-Mail Removed)> wrote in message
> news:fenvh9$jop$(E-Mail Removed)...
>
>>> See
>>> http://www.adslnation.com/support/filters.php
>>>
>> I see: 'the extra components are used to refine the frequency separation'
>>
>
> To a large extent that's just marketing speak.
>
> However that filter (the XF-1e) is an excellent filter while your other
> filter looks like it's probably rubbish.
>
> Problems with poor filters include:
>
> 1. ADSL signals entering modern phone often cause a background hissing
> noise.
>
> 2. Using the telephone can cause disruption to the ADSL signals causing
> dropped connections or with MaxADSL lower speeds that would be possible with
> good filters.
>
> 3. ADSL signals reaching a phone with caller ID display while it's not in
> use can stop the calling number displaying properly.
>

Hmm there was a bit of a hiss now you mention it. Now, in the quest for
ultimate speed (...) I've completely ditched any extensions around the
house I had and I've now got the router and my three GAP DECTs plugged
into the master socket via a XF-1e filter. Handily, I had cat5e cabling
in the stud wall with a faceplate on either end, one above the master
socket and the other right near my PC, from a previous voip application,
so I've still got my PC connected to the router wired connection. My
laptops/PDA use WiFi.

I was thinking of switching the master socket faceplate and filter for a
XTE-2005; is it worth it over what I've got now? It'd look better I suppose!

--
Abo