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Microfilter Problems!

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Microfilter Problems!

Hey there,

Having real problems trying to figure out where I should locate microfilters. I keep getting "No Dial Tone" when I try to connect using a BT SpeedTouch ADSL Modem.

I've got a diagram of the layout of the phones in the house, if anyone could shead any light on where to put the microfilters it would be VERY much appreciated.

http://www.molton.plus.com/random/broadband.JPG

Thanks in advance

[Moderators Note by Daniel (no7olivier) Image converted to link as it was streching the page.]
9 REPLIES
Community Veteran
Posts: 5,877
Thanks: 1
Registered: 05-04-2007

Microfilter Problems!

If I'm reading the diagram correctly everything is fed from the master socket, using splitters rather than hardwired extensions. As such you just need a filter at the master socket.

Take a look at http://users.plus.net/tutorials/id/13 for more information.
N/A

Microfilter Problems!

Appologies for my lack of terminology in advance!

Theres only one main wall socket in the house, and all the phones lead back to the main wall socket, so I'll give what you say a try, many thanks!
Liam
Grafter
Posts: 2,083
Registered: 04-04-2007

Microfilter Problems!

Essentially, all telephones will need to be plugged in through the phone side of a filter. In addition, you need to ensure that the modem doesn't run through any filters on the phone-side.

A common mistake I've seen is where someone plugs the filter into their master socket, then plugs an extention into the phone side of the filter which eventually leads to a splitter with a phone and a modem. Obviously then, the modem reaches the phone-side of the filter at the master socket - and thus the ADSL doesn't work.

Cheers,
Liam
jnwright
Grafter
Posts: 281
Thanks: 1
Registered: 05-04-2007

Microfilter Problems!

Filters have an ADSL socket which allows the high frequency ADSL signal to pass unhindered to a modem/router, a phone socket which allows the low frequency phone signal to pass to the phone and a line input which brings the ADSL and phone signals to the filter.
So, what you have to achieve is no ADSL signal going to any phone instrument, but the ADSL signal must get to the modem.

I am going to assume that you have one master socket and everything beyond that is done using extension cables. If you have wired sockets, it will be similar - I think you'll be able to work this out when you understand what has to be achieved. Here is a picture (yours modified!) http://i143.photobucket.com/albums/r149/jwcumbria/broadband1.jpg

The lounge phone must have a filter to prevent interference being heard in that phone and to stop that phone loading the ADSL signal.

Then the line going upstairs must not be filtered as you must allow the ADSL signal to get upstairs, otherwise it won't reach the modem/router.

The phone in bedroom 1 needs a filter in circuit. This again must be connected so that the phone in bedroom 1 is filtered so as to only allow the low frequencies to get to this phone. Don't connect anything to the ADSL socket on this filter.

The unfiltered line from the master socket splitter must continue onwards to bedroom 2 in order to get the ADSL signal to the modem/router.

In bedroom 2 you need another filter. This time connect the modem to the ADSL socket on the filter.

Beyond here you don't need the ADSL signal any more, so you can just connect any other other extensions such as bedroom 3 and the kitchen to the phone socket on this filter, splitting as necessary.

So, what you will have done is to not let the ADSL high frequency signals get to the phones, but allowed the ADSL high frequency signals to get to the modem/router.

Good luck!
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Microfilter Problems!

Thanks for all your responses guys, I'm about to go and put your ideas into practice! I'll report back.

Once again, Thanks!
Nick_Russell
Grafter
Posts: 553
Registered: 10-05-2007

Re: Microfilter Problems!

Quote
I keep getting "No Dial Tone" when I try to connect using a BT SpeedTouch ADSL Modem.


If you get this I'm sure it has nothing to do with filters. Filters are only necessary if you are using a phone and ADSL connection at the same time. Try connecting your modem directly to the master socket.

You could also try and establish an old fashioned dial-up connection from your PC and see if this will connect (assuming your PC has built in modem or you have an old external dial-up modem)

I would check wiring at each socket. Others have also reported removing ring wire (terminal 3) will help. Only terminals 2 and 5 need to be connected.

See here as well..

Useful explanation -
http://www.clarity.it/telecoms/adsl_bandwidth.htm

Guides -
http://www.telephonesuk.co.uk/wiring_info.htm

http://www.wppltd.demon.co.uk/WPP/Wiring/UK_telephone/uk_telephone.html
Liam
Grafter
Posts: 2,083
Registered: 04-04-2007

Microfilter Problems!

Hmmm yes, no dial tone generally means that the modem isn't synchronising with the exchange. Dial Up Networking was designed when broadband was non-existant - and so the closest error it can come up with is "No Dial Tone".

Are you able to remove everything else from the line, and plug ONLY the modem directly into the master socket. Then try it. If it works, then you know the problem lies somewhere with the wiring.
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Microfilter Problems!

Hi guys, sorry about the lateness of my reply, i removed the microfilter between the first splitter and the main wall socket

Thanks again for all your help!

Cheers!
oliverb
Grafter
Posts: 606
Registered: 02-08-2007

Microfilter Problems!

You might want to consider replacing your microfilters with one dedicated faceplate filter on the master socket. The downside is they're about £12 and you'll need a dedicated DSL extension to where your computer is located but the advantage is you don't need to have things hanging out of phone sockets so its much tidier and you can ofter get a noticable improvement in SNR leading to a faster or more stable connection.