Noise on a phone line and ADSL

Dear all,

I'm currently trying to share an ADSL internet connection over 3 PC's using a modem/router combo. Had a load of problems with flakey connections - fluctuating transfer rates etc...

After a lot of testing/analysis - and a few tech support calls, I think I might know what the problem is.

<b>I was hoping that anyone round here could shed some light on my theory - confirm or disprove.</b>

- We have a single phone line into the house which recently got upgraded to be digital so we can pipe 1mbit ADSL in.

- A previous resident has extended this phone line to almost every room in the building (at least 9 sockets, of which 6/7 work).

- ADSL requires the use of micro-filters on any phones, which we used for 1 phone originally (this fact led tech support to suggest it was a line quality issue), but now use 2 micro-filters: one for each phone.

Phone calls work fine, internet works intermittently - when it works, we get full bandwidth (110-140kb/sec). Just it has a tendency to time out on some pages, fail external pings and tracert's on-and-off...

<b>anyway, my theory...</b> The fact that we appear to have a large amount of extended cabling in this building, is it possible that any noise picked up by this cabling (e.g. from any mains cabling that it runs near to) is interfering with our ADSL signal? even if it's just "dead" wire and not actually used by any devices?

Provided this theory is correct...
- is there any way to diagnose the quality of a segment of line? like you can check Cat-5 cabling for breaks using voltage(?) checkers?

- is there any way of improving the cabling to get a better connection, or will I have to disconnect the extended cables?

Any help is greatly appreciated!
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  1. Not sure if you have done anything on this as I am late, but it definitely sounds like you have too many phone line connections. Tell me this, do you know if he paralleled(daisy-chained) or did he drop home runs from each outlet directly to the main box?

    If he paralleled them, that is either already your problem or will soon be one.

    I would get the phone company to come in for you (unfortunately for a fee) and get them to test for line noise and/or breaks. You have an advantage in running CAT-5(is this what you are running for everything?) in that it is twisted pair and reduces the likelihood of noise interference from external objects. If something is wrong internally, replacement is your only worthwhile option.
  2. Hello,

    Many thanks for the reply. I'm still fairly stumped on it all - still going through trying a few things, doing some research etc...

    The extension cabling, we recently found out, is actually split near to the source. The phone line comes from an underground source - going straight to a grey box on the outside of the house. This splits various ways (some cables split again at other identical grey boxes) and it's then drilled through the wall according to where the extension points are.

    Regarding the cabling - it looks like good quality cabling, but I've not been able to identify it. The Cat-5 cable that I mentioned is referring to the LAN. As in we have 3 pieces of Cat-5 connecting 3 PC's to the router - these work exactly as expected.

    It's looking like we may have to get an engineer in to look at what the problem is in more detail, but I still have hope that I can work something out :-)

    Thanks for your thoughts.
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