Filter position query

[#1]

I am setting up one of my friends on broadband next week and I just wanted to know whether it is absolutely essential to have the filter right next to the socket.
She currently has a double adaptor in the main telephone socket (downstairs), one leading to the downstairs telephone and the other one is just a telephone wire to the computer upstairs. What I want to do is to leave the double adaptor where it is, put the filter into the adaptor/downstairs line then put another filter at the end of the extension telephone wire adjacent to the computer upstairs.
As it is not wireless I can't think of any other way of doing it because I need the filter to plug the Voyager 210 into and I know that you are not supposed to have two filters in one line.
If anyone has any other ideas, please let me know, although it can't entail wiring for obvious reasons.

[#2]

Hi Poppy,
The current set up sounds like this:
SOCKET===ADAPTOR--------Telephone
                                 --------Computer
It will need to change to:
SOCKET===FILTER-----ADAPTOR-----Telephone
                             ------ROUTER
The fact that a fiulter is being used may negate the need to use the double adaptor, but if the computer is a long way from the socket, you'll either need to use a long CAT-5E network cable to go from the router to the computer, or to get an RJ11 extension cable to go from the filter to the router.
Sorry about the dodgy formatting

[#3]

SOCKET===ADAPTOR--------Telephone
                             --------Computer
James - this would work though wouldn't it? (Note: two filters here, one upstairs, and one downstairs)
SOCKET===-----ADAPTOR-----FILTER------Telephone
                                   ------FILTER------ROUTER
Its not ideal because of the amount of internal cable between the master socket and the router, but it does negate the need to run another cable (either cat5 or telecomms)

[#4]

Thank you for the reply James. I had a feeling that you would say that! The setup that you describe would then only necessitate the use use of one filter as I will put the double adaptor into the filter (the computer is upstairs).
The current extension cable terminates with the connector with the hole and she is currently using it for dial-up. I would like to continue to use this if possible because it is secured into the wall.
Obviously, this won't do for the Voyager (I will be using USB) so will  I need new cable or can I buy a connector which will include the same appertures as those in the filter?
The only other thing I can think of is to use the second filter adjacent to the Voyager and computer but I understand that you are not meant to use two filters on one line.
I suppose that I could try both ways but I am all for an easy life.
I know the amount of cable is not ideal but there is not much I can do about it. I am pretty hopeful that the connection will be OK because she lives within half a mile of the exchange.

[#5]

Don't know actually James.
I always thought that the filter had the be the first object coming in from the telephone socket.
I didn't think that basically double filtering a socket would work either.

[#6]

It does work, but you will likely lose *a little* signal due to the extended line length.
At home, I actually use:
Master Socket ------>  Splitter ------> Filter --------> Phone
                                      |
                                      +------------> ADSL (with no filter)
Works fine for me.
B.

[#7]

Heh. My home setup is.
MSOCKET--IPLATE--FILTER--ROUTER
    ||
SOCKET ---FILTER---PHONE
    ||
SOCKET----FILTER---SKY
    ||
SOCKET----FILTER---PHONE
I think it's a bit OTT for a 3 room flat (bedroom, bathroom, living room/kitchen) but nevermind

[#8]

Exactly - the filter doesn't need to be the first thing, its just its by far the easiest way to explain it, especially in a one-way instructive approach (ie, over the phone from CSC etc)
~So the accepted wisdom is to have " mastersocket|filter|Phone-phoneport & Router-routerport. "
It works because its easy to explain, and has the least opportunity for interference affecting internal wiring before the ADSL signal hits the router.
The key thing though is to filter every device connected to your phone circuit - only filter it once, and ensure you are using the correct port on each filter for its correct purpose.
There is a tradeoff in the example I gave above - its the potential for the internal wiring to have a negative effect on the ADSL signal as it is passed upstairs. The win is negating the need for any additional wiring.

[#9]

Quote from: Jameseh

I didn't think that basically double filtering a socket would work either.

Actually I don't think James' layout would be classed as double filtering as the adpoter/splitter can be thought of as two extension each with their own filter. Which is the correct configuration. Double filtering will be when a filter is fitted at the adopter and then at the computer/phone

[#10]

Again - the advice is not to double filter.
This could be because its easy to double filter in way that prevents either service working. (Filter for phone, then plug in another filter, and try to run ADSL from the second filter wouldn't work for example.)
So long as the double filtering is for the same service, it should work, its if you filter twice, once for each service that you get nothing working.
eg. (numbers are just to illustrate)
~1111100010101010101010
~
~If the first filter removes 1's and the second removes 0's, nothing gets through.
~If two filters remove 1's, 0's get through
~If two filters remove 0's, 1's get through.

Second Example (Ain't ASCII great?)

                                          |---PHONESIDE (Would work)
                |---PHONESIDE-~-FILTER---|
                |                        |---ADSLSIDE (Wouldn't Work)
line-~-FILTER-~-|
                |                        |---PHONESIDE (Wouldn't work)
                |---ADSLSIDE--~-FILTER---|
                                         |---ADSLSIDE (Would work)

[#11]

I believe your explaination may confuss laymen even more. Filters do not filter digital values. The filter is a low pass filter for analogue signals.  i.e. low frequency signals pass more easily to the phone and the high frequencies are attenuated. Low frequencies are speech and high frequencies are adsl.

[#12]

Oh dear - this gets very technical and a bit beyond me. Anyway, all replies very much appreciated - I think that I have a bit more understanding now.
Sounds like Barry has got the same setup as my original plan and it is OK for him so I will go for this.
It just confused me because having printed off all the stuff from the portal in readiness, every sheet said filter first (which I knew anyway). Will shout up if I get into bother.

[#13]

OK ... simple terms: on a filter/splitter only the phone side actually does anything, the DSL side is just a BT to RJ11 adapter.
IMO Double filtering may refer to two things:
1: Accidentally putting a phone filter on the extension you use for broadband, meaning that the DSL signal doesn't get through. This can be confusing to new customers.
2: Cascading two filters to get better filtering. This can sometimes be used with older DECT phones to reduce phone-DSL conflict.
Its probably possible to have too many filters on one line, I think the recomendation was four, the extra loading may affect voice quality or cause increased local feedback which can be disconcerting.
Not all filters are equal, there are review sites where filters are broken apart and investigated.
Don't panic, kittens won't die if your filtering is wrong, just tinker till it works. A single central faceplate filter can work wonders if your DSL signal is weak and avoids the need for all the boxes hanging out of sockets.

[#14]

You'd find my setup quite bizarre, though it is logical (to me).
ADSL filtered faceplate (currently Clarity, though I have an ADSLNation too)
Short lead to router. 10m LAN cable to main PC, rest wireless.
Filter (Excelsus Z-blocker) plugged into phone side of faceplate to recreate ring signal.
2 to 1 phone adapter plugged into that filter.
A pair of TwinTalk adapters plugged into the adapter - they need the ring signal.
Short CW1308 cable to phone socket from TT1 (home number), with 4-station DECT phone base station connected.
Longish CW1308 cable to phone socket from TT2 (business number), with BT Response 75 answerphone in it. Ring wire disconnected at both ends.
Another filter (Excelsus) plugged into answerphone (to recreate ring signal) and 2-way phone adapter plugged in that.
2 different DECT phone base stations plugged into the adapter, one single-handset one dual-handset. The single-handset requires the ring signal (built by Germans to a BT spec!).
Yes, I've got a lot of phones on 2 different numbers scattered around the house!

[#15]

Just an update - broadband now connected with the configuration as originally discussed. Speed is 1926kbps and the incoming/outgoing telephone calls are fine - no hissing or dropping of bb connection. Thank you all for the advice.