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View Full Version : How many microfilters ? (necrosan)



3Wheeler
2nd September 2002, 07:24 PM
I've just moved this thread to where, IMHO is it's proper place.

necrosan asked a supplementary question about the number of microfilters required in a "thank you" post (http://www.solwiseforum.co.uk/showthread.php?s=&threadid=1365) that was originally in the "Solwise -> Solwise Feedback" section. I gave an answer to the question there and necrosan asked for more clarification. I thought that I should really answer the question over in this part of the forum. So here goes! :)

necrosan asked what happened if ADSL became active on the line but not all of the telephone sockets had microfilters plugged into them.

The answer!
Apparently BT's policy is that all of your sockets should have microfilters in them even if you aren't going to plug in a phone at all of them. This may have something to do with preventing an RF interference "leak" at unfiltered sockets but I'm not too sure. The story goes that if you have to get a BT engineer to call in to fix a fault then they will tell you off if you are short of some microfilters. This is the policy that Solwise has to follow of course, to prevent problems with BT.

Now I'm going to tell you what actually happens in practice. If you have a socket that you intend to leave unused then this will not effect the operation of the ADSL or the other phones in the house.

I just performed a test in my house, by plugging in a phone without using a microfilter. This is what happened. If the phone was left on-hook then both incoming and outgoing calls from the other phone (filtered) in the house were unaffected and both phones rung on incoming calls. ADSL operation wasn't effected either. However if I picked up the handset on the unfiltered phone then the ADSL modem lost line sync and the ADSL stopped operating. It was also impossible to hear a conversation over the "rushing noise" of the ADSL modem. The modem re-synced once the handset was replaced and ADSL operation was restored.

Hope that this helps.

Steve

AndyL
3rd September 2002, 09:05 PM
To add...

My general recommendation to friends who ask is to put a filter into all sockets that have something plugged in.

But...

I generally am using a system where one phone socket in the house does not have a filter or anything plugged into it. My ADSL works fine at top speed and my voice lines are unaffected. (I have 2 sockets downstairs - 1 is phone via filter, other has nothing in it. Upstairs is one socket with ADSL and V90 modem leads plugged in).

At one stage the 'unfilled' socket in question had a filter but nothing else in it and the phone line quality was poor (v quiet). It was a dodgy filter. Recently a friend had the same experience - all quiet on the phone conversation front with a dodgy filter in the line. Filter replaced - no probs but since the system worked fine without it, I haven't replace it.

As a test, I am typing this with the downstairs phone plugged in with filter removed, whilst checking my 1471 message (last number caller). The phone quality is clear and the SAR715 ADSL connection is still running at the same rate (slightly patchy) as it was before I removed the filter (most days I can max out at top speed but at the moment I am d-l a large file from a poor server).

So my conclusion is:

your mileage may vary but a filter per socket is insurance against problems.

Hope this helps!

necrosan
6th September 2002, 02:52 AM
Since then, I'm now up and running on Eclipse ADSL via SAR310 PCI modem.

Only took 6 days from ordering to having an active DSL line. Major props.

No problems as yet. One (very rarely used) phone still doesn't have a microfilter in it, as I can't actually fit a microfilter in the socket without crafting a small hole in the floor. Which I odn't want to do. So I'm working on that.

The two used phone points are both filtered fine, and the remaining one has a sort of alarm thing fitted to it. So it just rings the alarm to alert someone in the room the phone is ringing. I don't see why this would need to be filtered so I left it.

Anyways, amazing service (and feedback) from both the kind people of Solwise and Eclipse ADSL. Thanks a lot!