Eskimo North

Hi...

I have been trying for well over a year to have my ADSL provider solve my issue, so far no luck at all.

SYMPTOM/S

Occasionally - sometimes at regular times, but sometimes not - my ADSL connection drops, and only connects sporadically if I work at it really hard - disable, re-connect, switch the router and/or modem off and back on again, hot-reset the router and/or modem, click on Repair/Close, whatever.

For perhaps 22 hours a day I have a fast connection, then it can just drop out for no discernible reason. I have lost so much time and work with this nonsense that I am now in the habit of Copying an entire email (or Post) to Clipboard before clicking on the Send button, just in case I get a blank screen telling me there is no connection.

I do know that sometimes the signal drops out just after 10:00am, sometimes just after 5:00pm, and is impossible to work with reliably for perhaps an hour, but can be as long as two hours. But that's not every day - there is no absoloutely regular pattern.

CONNECTION

I have an ADSL line coming to the south-west corner of the house. I saw that the internal phone wiring goes over ducts, around and over machines, fans, joists, etc., so the first thing I did to try and remove possible noise was to route a new cable for my personal phone line from the external box (BEFORE it entered the house) along external walls and into the house right at the computer location. I used copper shielded twisted-pair telephone wires from Radio Shack, and ensured all of the connections were clean, tight, secure, and shielded from the elements (weather).

"SUPPORT"

The problem was not solved. But for two hours after that I went through various procedures on the phone with Support, who seemed more interested in labelling it my problem than acknowledging that it could be something external.

I then exchanged my purchased "modem", which was still under warranty. The problem was not solved.

Recently I called Support again, who told me they ran a check on my line and the S/N ration was high, and that was probably the reason for my signal dropping. So they persuaded me to RENT another modem and see if the one that was replaced under warranty was the problem. But the problem is still not solved.

I am doing my best to try and figure out WHY I have service the vast majority of the time, but for perhaps two hours a day it all become a pile of crap.

POSSIBLE EXTERNAL NOISE

The nearest secondary road to my location is 100 feet, measured on Google Earth, so I can't see traffic being the reason. The distance to what I believe is the neighbourhood terminal (a substantial metal box about 5 feet high, 4 feet wide) is 2,000 feet along the road at the nearest major roadway junction - there are phone "stubby posts" along the way, but I think those are just for connecting the houses to the underground cable.

We did have a HAM radio operator in the area, but he died (and the house was levelled because a subsequent owner/tenant used it as a grow-op). We have not noticed any other antennas in the neighbourhood.

Could the computer fax-card connection be feeding noise into the line? And if so, why for only an hour or so a day?

HARDWARE

I am using XP Pro, with a DLink 614+_revB wireless router (with the wireless disabled). That feeds from a Thomson SpeedTouch 516v6 "router", which is connected to the externally-mounted and shielded phone line.

The router also feeds a signal to the power lines for the house network so my stepson downstairs can have access. The username/password combo is embedded in the router, so we don't need to log in every time we boot up. He has some gaming equipment down there, but the times he is using it do not match the times I have these problems.

One other thing... I use a 5.1 Gig portable phone, and Support told me that sometimes these units cause a problem by shorting out the line, which then affects the ADLS signal. I have tried disconnecting the phone line from that phone (no telephone service), but the problem persists. My wife tells me she also sometimes has a great deal of noise on her line (she has a separate voice-only line for the house).

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So, any ideas? Any suggestions?

We had some discussion via e-mail before the forum but the D-Link unit you are using is not one I am familiar with as we don't use them with our customers.

Most DSL modems though will have a status page for the DSL signal. The status page will show the S/N ratio. If you have a condition where the S/N ratio is marginal, it only takes a very modest increase in noise or decrease in signal to bring the signal to noise ratio below what is sufficient to decode the signal.

You need to find that status page and see what the S/N ratio is under normal conditions. For DSL 6DB is marginal, anything below that unusable, anything less than about 14DB won't be entirely solid. Things that can affect S/N are loop length, wire gauge, the number of twists per foot in the wire, and the insulator material used. Additional factors are noise caused by cross-talk from other pairs in the binding, and induction of noise from outside sources. Anything that unbalances the line will cause noise to be induced, so bad carbons (protectors), wet cable, etc, can all cause problems.

With DSL, any other device on the line that is not connected through a DSL filter will interfere with the DSL circuit. It's OK to have your 5.1 Ghz phone connected IF it is connected through a DSL filter, but it should not be connected directly without a filter.

AM broadcast stations and analog VHF TV stations are common causes of interference. These will usually cause audible noise in a telephone as well, you'll either hear the AM station, or you'll here a buzzing sound that changes with picture content with VHF TV stations. Later this month analog VHF TV goes away, so if that's causing you issues, they will be eliminated shortly.

So what I would suggest to start with is plug an ordinary phone into the line, through a DSL filter; and during a time when the DSL is down, pick up the phone, hit a touch-tone digit to get rid of dial-tone and listen carefully. You should hear silence; if you hear hum, hiss, crackling, other telephone conversations bleeding over, radio stations, or any other noise; that's a problem and should be reported to the telephone company and fixed.

However, because DSL uses frequencies into the MHZ range, it is entirely possible for an interfering signal to be completely inaudible.

If your signal is just marginal (near 6DB S/N) because of the length of the wire loop, the only way to improve that is to go to a lower speed. Sometimes a very marginal step-down can improve the S/N enough to turn a marginal connection into a solid one. Some modems have hidden firmware tweaks that can affect how aggressively they train, other times the only option is to have the telephone company to provision the DSL circuit for a lower speed. Here again, finding the status page is useful because you'll want to see whether the noise issues are upstream or downstream before you make any speed adjustments.

If your signal is marginal because of bleed-over from another pair in the same binding, sometimes the telco can cut your line to a pair in a different binding. The DSL protocol is such that you can only have so many pairs in a binding equipped with DSL before the cross-talk starts to become excessive and reduces the reach of each circuit.

There is also a new DSL protocol, DSL2, that if your DSL circuit isn't already on, can improve S/N somewhat. DSL uses a modulation scheme that breaks the bandwidth down into a bunch of narrow channels with guard bands between the channels. Training determines which of those channels is usable and sets the upstream and downstream speeds accordingly. DSL2 changes the modulation scheme in such a way that the guard bands aren't necessary and the full bandwidth can be used for data, which means for a given data rate, a lower S/N is tolerable.

So an upgrade to DSL2 protocol can be helpful, but I've also seen a lot of modems that have firmware issues that make them not work well with DSL2 when they operated fine with the old DSL, so that's a mixed bag, and usually not an option on a per subscriber basis anyway. It's usually something that happens when the telco replaces a DSLAM with newer equipment.

Some modems operate better than others under marginal conditions, so if you have a 6DB S/N, and it's loop-length related and not really something fixable; a different brand of modem may provide somewhat better results.

First, let me thank you in public for your assistance, freely given and extremely helpful and educating (to me, anyway... as a part time programmer/webmaster and past airline pilot with technical leanings).



Sorry, no s/n measurement. I have searched the PDF manual downloaded from Support and gone through all of the tabs and options, there is no s/n measurement. Which is why I asked if there is third-party software to get that valuable measurement.



All devices attached have filters. But the old anomaly remains, the line still works well 22+ hours a day and suddenly drops out for relatively short periods.



None nearby (that I know of).



Will do. My wife does hear hoise on her line - which almost drowns out the dial tone - and mine does the same. I smell telco problems, but my provider uses the telco lines and I get the impression the last thing they want to do is ask the telco ANYTHING (probably for $$$$$ reasons).



I go from the external terminal box directly around the house externally to the wall where my computer is. The 2-pair shielded cable I use is marked for telephone use by Radio Shack, and the other pair is not being used. No second pair in use = no noise from that source. And they are shielded, so neither pair is acting as an antenna.



As indicated, that would be a local telco issue, and probably a big $$$$ issue for my provider. Here in Canada, Ma Bell still rules the roost and seems to charge big bucks even for just answering their phone (if you can ever really speak to an actual real live person - the old-style ones with blood and veins - instead of paging interminably through menus towards your inevitable cut-off dial tone).



I will bear that in mind... I bought my modem rather than rent it (I tend to think long-term) and once I return this rental one I will seriously consider that. Do you have any recommendations? Are there different equipment signals from different telcos?

And do you have a suggestion for a good recent-reliable model router, one with the s/n status feature? The one I have now does the authentication for me, that would be a major plus, too (I don't need wireless any more).

Again, thank you very much for your help,

Jim

Personally, I haven't seen any that are 100%, but the ActionTec units seem pretty solid and give you a lot of visibility over what is happening. It's really hard to believe that nowhere in that unit is there a status page as it is so fundamental to troubleshooting.

Sorry, Nanook, but I'm stumped up here in the Great Frozen White North.

Can you help a bit with brands and model numbers of routers which have built-in s/n ratio monitors and self-authentication (username/password) features? I have been asking questions at computer stores here in northern Toronto (Canada) all day and none of the tech sales people have a single clue what I am talking about.

TIA

I'm really not that familiar with that many models. The GT701WG that I have does. The Zoom X6 does. I can't recall ever seeing one that doesn't which is why I am still having a hard time believing.

Hi, Nanook...

Thanks much for your advice and assistance...

I started another thread elsewhere and also got advice and assistance there. Here it is...
http://www.tomshardware.com/forum/25278 ... se-issues/

I suspect the final verdict is not in. Support is testing and tweaking without the intermittent noise on the line, so they think all is well. Telling me I am up to 4 Mbps doesn;t help much - I never use that much speed anyway - but I guess every little bit helps!

Thanks again...

Jim