I want to run cat5 cable in my house to replace the current telephone wire. I hope to increase the SNR for my ADSL connection.
So I was thinking in using one pair, and I read somewhere that I should use the brown or orange pair, but I was thinking that leaving the other pairs floating isn't it bad? can I just use the 4 pairs in parallel? Should I just loop every pair back? ground then?
What do you guys think? It is my desperate plan hopeless?
You don't say where in the world you are based which might help with possible teleco quirks.
I wouldn't underestimate the effect that even a few metres of untwisted cable can have - especially if there's a lot of electrical noise in the vicinity. 1.5m of untwisted cable lost me about a megabit and a half when I had ADSL (have VDSL now) - quite a big deal when the fastest the line would go was 3Mbs
-1Otherwise I agree with everyone who has said you probably won't see much improvement swapping decent quality twisted pair telephone wiring for cat5e.
However I don't think signal to noise ratios are your problem - at least not when that snapshot of your line stats was taken and perhaps not in the way you think.
One piece of information which would be useful is how long your "local loop" is - i.e the length of the line from the exchange to your premises.
For a line attenuation of 48dB downstream I'd expect 3.5 to 4.5km (roughly 10-12dB attenuation per km). If a lot shorter than this you have a bad line. If longer a very good one.
Then looking at the SNRM 13.8dB is actually quite high - don't forget this is
not the signal to noise ratio but the SNR
margin - i.e how much worse the SNR can get and the modem still be able to maintain the current sync speed.
When DSL modems negotiate the sync speed they don't negotiate at the fastest speed possible but slightly lower - this allows a margin for the line noise to get a little worse without needing to re-sync. Most lines vary in their noise levels throughout the day so if this were not done you'd get huge numbers of line re-syncs.
The default margin is 6dB for most telecoms companies on a new line - the system then gradually "learns" where it needs to be set for reliable operation.
Finally note the "max attainable" speed is currently over 8Mbs
-1 despite a sync of 4Mbs
-1 So it looks as though either you are on a fixed 4Mbs
-1 service for some reason
or you line has a lot of noise variation through the day. The default SNRM starts at 6dB and is adjusted in 3dB steps in the range 3-15dB, thus a current SNRM of 13.8dB might suggest a 12 or 15dB target for your line which isn't great.
Those who have said you don't need a filter if you don't have any phones connected are correct. The filters connect the DSL modem directly to the line and then provide a low pass connection for the phone - their main function is really to keep DSL signals away from the phone. However if the modem is plugged in close to where the line enters the building and the extension wiring is still present it might be worth putting a filter in to isolate the extension wiring. Or just disconnect it.
You need to do a couple of things. First check you're not on a fixed speed service. Then repost stats immediately following a re-sync (this means you can tell what your default SNRM target is).
Then I'd get a copy of DMT tool and look at the stats over a few complete 24 hour periods. If the SNRM is falling much lower during some point in the day that might give you a clue. If it's overnight then MW radio pickup is a common culprit and if your local loop has long overhead runs there might not be much you can do about it (isolating even unused extension wiring stops it acting as an antenna which is why it can be helpful).
If the SNRM is worse during the day there might be interference from electrical equipment in use at that time - perhaps in your house, perhaps somewhere close to the line running back to the exchange.
You also need to look at what sort of speeds you get when you use the "test" socket if you have one. For UK BT connections that's the one
inside the master socket - using that will isolate all the extension wiring. I'd be slightly careful about interpreting the result given the stats that you posted but if you get a big jump up which is then maintained over at least 24 hours it might well be the extension wiring that is the cause of your low sync speed.