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.