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[hake]

Downstream sync speed stable at 4704kbps but why is upstream speed only 384kbps?  The router just won't sync at 448kbps.  It's a puzzle and I am stumped.  It's not really a problem since uploads are not a big feature in my Internet life.  It doesn't affect normal browsing.  I'd just like to know if there is a possible latent problem.

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[roseway]

That's fairly typical of what can happen with a noisy line. The sort of interference which you can hear on the phone as a random crackling noise tends to be at its worst in the lower frequencies which are used for the upstream part of the connection. As it happens, I'm suffering from exactly the same thing at present.

I'm not saying that your situation is the same, but it's one possibility.

[hake]

Thanks for that roseway.  I now know that ADSL works by splitting the signal frequencies between downstream (high) and upstream (low) so that two way traffic can be on one pair of wires.  Obvious really but some (like me) need to be told.

Regarding the noise, none is audible on my voice telephone.  The quality is very high with no crackling apparent.  I do anticipate crackling on my pork this lunchtime though.   

[roseway]

>> I do anticipate crackling on my pork this lunchtime though.

Lucky chap

Even if you can't hear any noise on the line, that's still quite likely to be the cause. Your upstream noise margin is quite low, which suggests that it's done the best it can in a rather noisy situation. Swapping your filters or changing to a different router might help, but if it doesn't cause you any problems it may well not be worth the bother. But I would certainly keep an eye on it in case it gets worse.

[UncleUB]

Just to add to Eric's comments,my upstream is always round about 380kbps.It doesn't cause me any problems so I leave well alone.

[J.Man]

This is a pretty confusing topic as I'm in a similar Position as I sync at 8,096kbps Downstream and 276kbps Upstream

[roseway]

This is getting rather interesting. I wonder if there's any connection between this behaviour and certain routers or chipsets. What routers to you people use?

[Ezzer]

My theory is that any piece of equipment will have it's natural resonances which will either recive or transmit EMF at prticular frequencies/wavelenghts.

Much like if you have a string instument producing a note, if you have another string instument nearby then by carefully tuning a particular sting you'll find it will start to miracuously sing the same note. It has to be in perfect harmony but from the sound energy in the air from the first instrument will be picked up by the second.

Electrical equipment will behave the same way, In fact thats precicely how a radio works and when you tune a radio to a station it's exactly like tuning the 2nd string instrument.

All the issues on this form ref SNR are a form of this. here it's part of your electrical equipment thats the cause and effect.

If your unlucky then part if your router will be in tune to a bit of noise nearby, If another make of router bwhavea better then it's chance that part of it is different to the first one and that part is not in tune to the noise.

alternatly if the noise is in tune to a critical component to the dsl frequencys then changing the router won't help because the relavent component has to be in tune to the same thing.

We're engulfed with all sorts of EMF, itbs just in the csae of DSL we're asking so much of the proccess -tbs potentialy falible to EMF ina way we don't notice with most other things.

Another exsample is how many times have you heard those funny pulses on a tv,radio,speakers etc casued by a nearby mobile, same type of effect

[hake]

Doctor Johnson observed a dog walking on its hind legs.  "It's not so much remarkable it's done well, rather that it's done at all." quoth the great man.

ADSL broadband is a bit like that dog.  It's a valiant attempt to wring more value from an ancient telephone system and it often works well but it ain't half sensitive to its environment.  As ezzer hints, there must be loads of interference sources all the way to the telephone exchange.

BTW, my speeds are now 3840 kbps (down) and 448 kbps (up).  SRN margins are now 18.5 (down) and 14 (up).  It flipped at 1730 hours this evening after 74 hours at 4740/384 kbps.