That syncing feeling!

For the past two months my sync has steadily fallen, nothing has changed at this end and my ADSL installation is just as it should be.

I used to sync in the upper 5 meg region to lower 6 such that my IP Profile was at least 5 Mbps and sometimes 5.5. Now I'm lucky to see a profile of 4-4.5. My router is the 585 v6 and current stats are much the same as they always have been for this time of day, 14.40:

0 days, 3:19:22
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 5,376
Data Transferred (Sent/Received) [KB/MB]: 849.00 / 1.96
Output Power (Up/Down) [dBm]: 11.5 / 19.5
Line Attenuation (Up/Down) [dB]: 25.0 / 41.0
SN Margin (Up/Down) [dB]: 22.0 / 14.0
Vendor ID (Local/Remote): TMMB / ALCB
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 0 / 32
CRC Errors (Up/Down): 0 / 0
HEC Errors (Up/Down): 0 / 0

At night, if I'm lucky, this sync will be held and the margin falls to around 7dB otherwise it drops to the 3 meg region and the SNM up to ~14. Why has it gone down? The speech circuit is fine, my ISP has tried resetting the target nm to 6dB and my sync rose to 6816 @ 7.5dB but it didn't last!

Use DMT Tool to fix it.

Thanks but it won't work with my router, tried it before even if I "unlock experimental area" it opens for a few seconds then vanishes. In any event, it wont solve the inherent problem.

Your router is in the list of supported routers for v7.35.

SpeedTouch 585 firmwares above 6.1.4.3 can't be tweaked but will still work with other aspects of DMT.

That's quite a drop in night time noise margin, 7dB, mine drops by about 5dB, and I thought that was a bit much. If the noise margin is 15dB (I'm guessing) at sync, that's probably why the sync speed has dropped off. The default is 6dB, rising through 9, 12, up to 15dB if there have been connection problems.

In reply to a post by lunarjetman:

SpeedTouch 585 firmwares above 6.1.4.3 can't be tweaked but will still work with other aspects of DMT.

Mine's v6.2.17.5 and as you say other aspects work OK.

In reply to a post by Andrew_W:

Mine's v6.2.17.5 and as you say other aspects work OK.

I presume you've done all the usual stuff like checking the ring wire and so on? That does look like a justifiable target margin of 15dB based on what you describe.

The question is what is causing that huge noise variation, and the final spike that causes the re-sync. After the re-sync the margin will rise back to 15db, as you describe. That's why it's called the "target" margin around here - it's the figure used to set your sync, in conjunction with the actual noise at the time. Which at night is high for everyone, and stupidly so for you.

Have you reset the router to factory defaults at any stage using the hidden button at the back? Have you got one side propped up to avoid overheating as the 585 is very prone to that? Borrowed another router to test what happens? Swapped filters. All that guff .

In reply to a post by dieselglider:

That's quite a drop in night time noise margin, 7dB, mine drops by about 5dB, and I thought that was a bit much. If the noise margin is 15dB (I'm guessing) at sync, that's probably why the sync speed has dropped off. The default is 6dB, rising through 9, 12, up to 15dB if there have been connection problems.

Quite but why does it vary so much? Yes, noise at sync is usually around 15dB (daytime) but I leave the router on all the time until it drops sync.

In reply to a post by RobertoS:

I presume you've done all the usual stuff like checking the ring wire and so on? That does look like a justifiable target margin of 15dB based on what you describe.

The question is what is causing that huge noise variation, and the final spike that causes the re-sync. After the re-sync the margin will rise back to 15db, as you describe. That's why it's called the "target" margin around here - it's the figure used to set your sync, in conjunction with the actual noise at the time. Which at night is high for everyone, and stupidly so for you.

Have you reset the router to factory defaults at any stage using the hidden button at the back? Have you got one side propped up to avoid overheating as the 585 is very prone to that? Borrowed another router to test what happens? Swapped filters. All that guff .

Filter faceplate fitted by BT three years ago! Could that have failed?

Router runs cool and would a reset to factory defaults be beneficial or otherwise? And yes, tried another router and problem is worse (Lynksys). The 585 is more reliable on my line.

Filter faceplate fitted by BT three years ago! Could that have failed?

It's possible, but I would have thought you would see problems all the time.

I would try running RouterStats to monitor things closely. Perhaps you are having a noise spike that's upsetting things?

In reply to a post by Andrew_W:

Filter faceplate fitted by BT three years ago! Could that have failed?

I don't see why it couldn't. So I suggest a few days trying using the test socket inside, and a filter if you need to connect the phone. Obviously something has gone wrong somewhere to cause your deterioration.

Router runs cool and would a reset to factory defaults be beneficial or otherwise? And yes, tried another router and problem is worse (Lynksys). The 585 is more reliable on my line.

In that case probably not worth it, especially if you have any settings other than username and password in there.

Equally, if that's all you have to re-enter, and you remember the password, it can't do any harm. (You leave it switched on, then gently but firmly push the end of a paperclip into the reset hole, release when the light(s) on the front start to flash.

Not got a new Sky box just before this started, or anything else? New DECT phone? Sky boxes occasionally need double filtering, or used to.

RouterStats is better than DMT for graphing, I agree.

An hour and a half ago, the damn thing re-synced and my sync is now 3872 and noise margin of 15.5dB.

No Sky box, had a DECT phone for years so will try a factory reset for the hell of it! There is one slight possibly related cause of this problem. My daughter lives about 300 yards away and her phone line shares the same overhead multicore cable as mine. She reports slight crackling on the voice circuit that I can't hear when she phones me but BT say there is no fault on the circuit. Possible crackle crosstalk if there is such a thing?

I will try the test socket suggestion but if the faceplate filter has failed, wouldn't I hear the BB signal on the phone?

Edit: Tried the reset, sync now 3680 and SNM 17 dB

Edited by Andrew_W (Fri 27-Feb-09 20:24:13)

Don't forget to try the "Quiet line test" on your own phone ......dial 17070 and press for option 2

If you or your daughter hear any noise, it can be reported to BT as a line fault.

On no account mention anything about problems with your BB connection to them.

In reply to a post by Apprentice:

Don't forget to try the "Quiet line test" on your own phone ......dial 17070 and press for option 2

If you or your daughter hear any noise, it can be reported to BT as a line fault.

On no account mention anything about problems with your BB connection to them.

Thanks but done that already! Daughter has reported it and BT say no fault but would accept 140 odd quid to come out and prove it!!

Tried the reset, sync now 3680 and SNM 17 dB

That's expected in a way given the high moise margin. What the 17dB indicates though is that between the re-sync and the reading of the stats the margin rose by 2dB - in other words the actual noise fell. Which is again a wide swing in a short time.

If you re-sync after 9am it will be faster. Preferably using the test socket, not the master socket, as I said before. Let's hope it improves the stability, if not the speed.

Thanks Bob for your ongoing help!

Well first, I have bought my daughter for her birthday a DG834Gv5, Firmware V6.00.25 So, I unwrapped it and connected this morning and the result was this about 5 minutes ago
Speed 4288 kbps 448 kbps
Line Attenuation 44.5 db 25.0 db
Noise Margin 17.5 db 23 db

This time of day a resync with the 585 usually results in a sync above 5meg at least.

The down line att shows an increase over the 585 as does the noise margin for this time of day. Next I went to the master socket filter faceplate fitted as I said, by BT to try an in-line filter. This faceplate has BT ADSL V1 printed on the front and the ADSL socket is a non-standard (to me) phone type socket (not RJ11) so of course I couldn't connect the plug from my router to the in-line filter or the test socket, it only fits the ADSL connector on the faceplate. I don't have a suitable cable long enough to connect the test socket to my router upstairs and moving the router downstairs is complicated!!

Perhaps if I buy a new faceplate and change the plug on the end of the router cable to suit as assume a normal filter faceplate would have a standard RJ11 connector for ADSL?

Edit: Just reconnected my 585 and get this:

Bandwidth (Up/Down) [kbps/kbps]: 448 / 4,960
Data Transferred (Sent/Received) [KB/KB]: 1.00 / 1.00
Output Power (Up/Down) [dBm]: 11.5 / 19.5
Line Attenuation (Up/Down) [dB]: 25.0 / 41.0
SN Margin (Up/Down) [dB]: 22.0 / 15.5

Still not good.

Edited by Andrew_W (Sat 28-Feb-09 11:13:00)

I was reading about the new DG834Gv5 last night.

It seems this uses the Conexant chipset rather than the v4's Broadcom (like your 585v6) - it seems people with line issues usually seem better off with a Broadcom based router from what I've tried and read.

Interesting thanks. My daughter is not so fussy as me when it comes to ADSL . She is currently using a V4 (of mine) so I'll get that back but Dad is very generous and giving her an Asus Eee too I don't want so she'll need wi-fi

BTW Why can't I get your line stats? I'm rural too!

Edited by Andrew_W (Sat 28-Feb-09 11:46:14)

Following on from this, my router has not re-synced for 4 days now but what I have done is move the DECT phone base unit (i.e. the transmitter) away from the router as the two were only 6" apart. Although I have a filter faceplate I also added an in-line filter to the DECT phone and at the time I plugged it in I had Routerstats running and it showed a brief downward blip on the noise figure as the two made contact. Suggesting what???

Stats currently are:

Uptime: 3 days, 23:14:45
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 5,312
Data Transferred (Sent/Received) [MB/MB]: 75.27 / 488.74
Output Power (Up/Down) [dBm]: 11.5 / 19.5
Line Attenuation (Up/Down) [dB]: 24.0 / 40.0
SN Margin (Up/Down) [dB]: 22.0 / 12.0
Vendor ID (Local/Remote): TMMB / ALCB
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 0 / 67,588,626
CRC Errors (Up/Down): 0 / 772
HEC Errors (Up/Down): 0 / 544

At night the SNM falls to around 7/8dB about the same as before but at least it stays synced!

A brief downward blip could be just due to the making of the contact - the making of any electrical contact can be imperfect for a fraction of a second. Some of our light switches let out a visible flash when switching on.

Otherwise, you seem to have found the problem - the DECT base too close to the router.

Otherwise, you seem to have found the problem - the DECT base too close to the router.

Hope so, all I wish now is the sync rate to increase to what it was. The daytime SNM is currently about 3dB lower than usual, is that a good sign?

Resurrecting this thread, now the opposite is happening! Is it possible BT have improved my rural line? I have been able to maintain sync ~6meg on lower SNMargins over the past two weeks and now following a brief power cut this morning I find this

Uptime: 0 days, 0:44:49
Modulation: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 448 / 7,296
Data Transferred (Sent/Received) [KB/MB]: 242.00 / 1.48
Output Power (Up/Down) [dBm]: 11.5 / 19.5
Line Attenuation (Up/Down) [dB]: 25.0 / 40.0
SN Margin (Up/Down) [dB]: 24.0 / 9.0

Target SN Margin has dropped to 9dB by the look of it. Anither fortnight try a re-sync yourself and see if it has gone to 6dB!

One happy bunny?

In reply to a post by RobertoS:

One happy bunny?

So far, but suspect it wont last when it goes dark tonight At least it shows what the line is capable of on a good day and the wind in the right direction

Well, the good news is that the days are now getting longer, so the noise caused by ionospheric reflections of MW signals will now slowly reduce until mid-summer

I know, can't wait! Get the roof off on me motor too

Well, miracles can happen! Maintained 7296 sync overnight, checked last night about 10pm and noise margin was 4dB now at 8.50 am is 11dB. Something has improved somewhere BT speedtester currently "busy" !

In reply to a post by Andrew_W:

Well, miracles can happen! Maintained 7296 sync overnight, checked last night about 10pm and noise margin was 4dB now at 8.50 am is 11dB. Something has improved somewhere

I can't see the target margin is going to drop any further; a lower target will result in a higher sync, so your lowest margin of 4dB, will drop to 1dB (ish), causing too many errors, and a probably re-sync.
You still have a massive day to night swing (7dB), which if you're already using the 'test' socket or an ADSL filtered face-plate, and have your router next to the master socket, you're going to have to live with.
As a comparison, from a significantly longer phone line, my day to night margin swing is around 2-3dB.

I do have a filter faceplate and the router is about 8 feet from it. I will be quite happy if I can maintain around the current sync rate.

BT has now recovered and currently I get this:

Test1 comprises of Best Effort Test: -provides background information.
Your DSL connection rate: 7296 kbps(DOWN-STREAM), 448 kbps(UP-STREAM)
IP profile for your line is - 5500 kbps
Actual IP throughput achieved during the test was - 5101 kbps

In reply to a post by Andrew_W:

BT has now recovered and currently I get this:

Test1 comprises of Best Effort Test: -provides background information.
Your DSL connection rate: 7296 kbps(DOWN-STREAM), 448 kbps(UP-STREAM)
IP profile for your line is - 5500 kbps
Actual IP throughput achieved during the test was - 5101 kbps

It hasn't quite recovered; the IP profile for a maintained sync above 6816kbps is 6000kbps, so your sync has been below that level at some point over the last five days.

No, I meant that the BT tester has recovered from its overnight rest We shall see what happens over the next five days!

Now what's happened?

After almost four days of stability router lost sync overnight and this morning was ~1.8 meg with noise margin of 25dB. Rebooted about 10 minutes ago and now have this:

Test1 comprises of Best Effort Test: -provides background information.
Your DSL connection rate: 6240 kbps(DOWN-STREAM), 448 kbps(UP-STREAM)
IP profile for your line is - 1500 kbps
Actual IP throughput achieved during the test was - 1377 kbps

Noise margin now 12.5 dB

Well the 1500 profile is correct due to the 1.8Mbps sync. But whereas we thought the target margin had dropped to 9dB, if the re-sync this morning came at 12dB then it has gone up again. You should be able to see what the figure was from the RouterStats graph and/or log.

How much has the noise margin been varying over 24 hours since you got the high sync a few days ago?

What you need to start doing I suggest is a daily read of the error stats. See if there is anything that might have made the DSLAM up you to 12dB

The RouterStats log was not enabled but it is now! The noise margin with the high sync seemed to vary from 4 dB during darkness to 11/12dB during the day.

Unfortunately I should have had a look at the 585 v6 events log before rebooting to see how many times it lost the connection overnight, I suspect more than once.

In reply to a post by Andrew_W:

The RouterStats log was not enabled but it is now! The noise margin with the high sync seemed to vary from 4 dB during darkness to 11/12dB during the day.

Routerstats saves the graphs every so often so you should find those somewhere and move easily between the saved chunks with Windows Explorer. (Not Internet Explorer). Or you can scroll back the main graph by grabbing the graph line and dragging it sideways.

just a suggestion that could help you here, if you cannot stable the line out it could be worth checking if there is a decent LLU ISP in your exchange (Not TT!). With having such dramatic shifts in syncs your ip profile is going to pot. On an LLU service you will be able to make much more use of your sync rate when it is working fine. However this is just a "damage limitation" not a solution if you are in need of high speeds.

In reply to a post by Anonymous:

just a suggestion that could help you here, if you cannot stable the line out it could be worth checking if there is a decent LLU ISP in your exchange (Not TT!). With having such dramatic shifts in syncs your ip profile is going to pot. On an LLU service you will be able to make much more use of your sync rate when it is working fine. However this is just a "damage limitation" not a solution if you are in need of high speeds.

That's a good point. We haven't asked which exchange it is.

Solving the noise fluctuation looks like it might be impossible given the overhead supply to the area, but a non-profiling ISP could make it less annoying.

Nice thought but where I live we are lucky to have ADSL , let alone LLU!! The exchange in question is Tetford, Lincolnshire.

Sam Knows indicates that I am 2.16km from the exchange which will be reasonably accurate as my phone line follows a straight road from that village. All but the last 500mtrs is underground but the overhead bit does pass under (at right angles to) an 11kV three phase power line supplying my home

Regarding RouterStats logs, Bob, there were a few chunks saved but nothing useful. Dragging the main graph back didn't go far enough in time. Perhaps I should leave my PC on all night?

Edit: Wrong! Just measured it in the car and it's 2.1 miles or 3.3796224 kilometres

Edited by Andrew_W (Tue 24-Mar-09 17:12:54)

In reply to a post by Andrew_W:

Sam Knows indicates that I am 2.16km from the exchange which will be reasonably accurate as my phone line follows a straight road from that village. All but the last 500mtrs is underground but the overhead bit does pass under (at right angles to) an 11kV three phase power line supplying my home

Regarding RouterStats logs, Bob, there were a few chunks saved but nothing useful. Dragging the main graph back didn't go far enough in time. Perhaps I should leave my PC on all night?

Not sure how healthy/unhealthy that wiring is. Could even depend on the wind and passing swarms of bats.

When I wanted to trace something like that the only solution was to leave things on 24/7 for a few days. That way you get to see the pattern of regular changes, and detailed timings of spikes.

It might be worth it for a few days.

In reply to a post by Andrew_W:

...Perhaps I should leave my PC on all night?

I've only been dipping in and out of your thread - but seeing you mention that made me think.

Why don't you turn your router off when you turn your PC off at night?
That's what I do and it seems to work for me - my line can be rather dodgy, so I turn my router (and PCs) on in the morning and off at night. That way it reduces the chance of anything affecting my IP Profile etc.

Just a thought...

That's another way. Quite good in the summer when there is daylight in the mornings so noise is low. Not so good in the winter - you tend to get a permanently low'ish sync/profile then.

I don't start 'work' until 8.30ish so that's not a problem for me

Could even depend on the wind and passing swarms of bats.

It's been suggested that the frequencies used by said bats in their "radar" techniques could interfere with ADSL

Why don't you turn your router off when you turn your PC off at night?

I had thought of that but my loved one tends to get up in the middle of the night so if she switches the router on during darkness to send emails around the planet, could make matters worse!!

In reply to a post by Andrew_W:

It's been suggested that the frequencies used by said bats in their "radar" techniques could interfere with ADSL

Do Andrews dream of electronic bats?

No, only cricket ones