Do unused phone sockets need a microfilter?

I really feel I should know the answer to this one but I've searched various forums without finding it!

As the subject says, I'm trying to determine whether or not phone extension sockets that are UNUSED should have a microfilter in them.
I can't think of any reason why they should need one, since the filter wouldn't be connected to anything, but I'm sure I have previously read advice that adding filters even to unused extension sockets will help - I think the rationale might have been to ensure impedences were matched along the whole of the phone wiring, to avoid signal reflections that might affect SNR etc.

I am overseeing an installation for someone whose line is a bit marginal, so am interested to know whether the suggestion to add filters to unused sockets is an old wives' tale or not ......

Thanks
Phil

No. Microfilters are not needed for phone sockets that are not being used for anything (regardless of whether it's ADSL or plain old phone usage).

However, seeing that you are helping out someone else's installation it may be prudent to put one in, just in case in the future they decided to put a phone into the currently unused socket. Putting a microfilter into the unused socket now won't make the slightest bit of difference to the lines stats but it will later on if the owner puts a phone into it without there already being a filter present.

Either that or...

1) tell them never to use the socket
2) or get a blanking plate to prevent them from using it
3) or simply return in the future with another microfilter when they wish to make use of the socket.

Phone extension wiring can pick up noise which can affect ADSL performance. The best thing to do is to fit a filtered faceplate on the master socket, which effectively filters all the extension wiring, preventing noise pickup. Obviously the socket which the ADSL modem is connected to must remain unfiltered, and should be as short as possible.

Edited by deleted (Fri 06-Apr-07 17:27:18)

Thanks for the posts.

Unfortunately in this instance the router is on an extension, and so I can't filter at the master socket. If appearance is important I'll suggest filtered faceplates on master & extensions but I suspect a decent in-line filter in each will probably do here.

Cheers
Phil

You have 2 options available for the long extension:

1. Run that extension in Cat5

2. (Preferred) Move the router next to the master socket, and run Cat5 ethernet back to the PC(s).

3 options

In reply to:

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1. Run that extension in Cat5

2. (Preferred) Move the router next to the master socket, and run Cat5 ethernet back to the PC(s).

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3. Move the router next to the master socket, and use ethernet over mains to the PC(s) or switch.