Thank you Roberto and thankyou everyone who has helped here. I have been trying this on and off for a few months now since joining PlusNet. It is a uniquely PlusNet issue because of their curious 40/20 package. I will be posting on the forum there soon as well in case it helps anyone else.

I think this is a good example where forum collaboration really helps. Partly because of lack of HG612 CLI documentation it would have been a very long time before any one of us alone had come up with an answer.

Edited by StephenTodd (Mon 26-Jan-15 11:13:59)

In reply to a post by StephenTodd:

Thank you very much.

xdslcmd configure --maxDataRate 50000 25000 75000 didn't seem to force a resync by itself.
But xdslcmd start --up --maxDataRate 50000 25000 75000 did the trick.

I am now seeing a 14.5 SNR, which should be pretty robust against most fluctuations and reduce risk of getting put on interleaving.
As I expected, speedtests are unchanged. http://www.thinkbroadband.com/speedtest/results.html...
BT wholesale showing 48.4/20 profile, 38.25/17.38 speedtests.

Down            Up
max:            75080          22355
path:           49999          19999
SNR (dB):        14.5            7.1

R:              16              16
N:              254             254
I:              254             127

INP:            0.00            0.00
D:              1               1
delay:          0               0

I was very surprise this tweak does work in your favour! But it a question of time that DLM might adjusted it back to where they used to be in due course!

In reply to a post by adslmax:

I was very surprise this tweak does work in your favour! But it a question of time that DLM might adjusted it back to where they used to be in due course!

It will be interesting to see.

From Chrysalis' comment the configuration settings will certainly get lost if the modem reboots.
I suspect that the xdslcmd configure --maxDataRate 50000 25000 75000 part means it will use those figures for resyncing until then.

It may be that DLM will decide I can go faster, and so schedule early morning resyncs.
However, as it looks as if that configuration of the modem will mean that the resyncs still sync at the modem limited speed.
I don't think any of knows enough about the system that we feel we could give reliable predictions about how it will behave.

In ADSLx days I found unsaveable SNRM tweaks survived re-syncs from any cause, but not reboots.

yes if the resync is not initiated by the modem it may survive I am just not sure, defenitly wont survive a reboot.

This thread highlights why I think a 40/10 wholesale package is better for those who only want 40mbit, as it grants extra stability.

Edited by Chrysalis (Thu 29-Jan-15 17:34:23)

In reply to a post by Chrysalis:

This thread highlights why I think a 40/10 wholesale package is better for those who only want 40mbit, as it grants extra stability.

That's what DLM is supposed to be for. I'm sure PN did their trials and they indicated that this kind of thing is the exception rather than the rule.

In reply to a post by Chrysalis:

This thread highlights why I think a 40/10 wholesale package is better for those who only want 40mbit, as it grants extra stability.

who only want 40mbit download and only want 20mbps upload.

It looks as if my change is sticking, so far at least. Downstream errored seconds are down for around 100 per day to around 10 per day. Though I must admit that my line appeared to be perfectly stable even at the 70Mbps 6dbSNR setting.

except stability via a nice snrm buffer is preferable to added artificial latency.

I didn't notice at first that you were replying to an earlier post and not my more recent one. Still, most of what I say here still applies.

In reply to a post by Chrysalis:

except stability via a nice snrm buffer is preferable to added artificial latency.

Exactly why I wanted (and finally managed) to change my sync speed; so that it syncs with higher SNR. This did not have any immediate effect on latency, but reduced the risk of the kind of errors that could cause DLM to step in and add interleaving and thus increase latency.

My attempts to change it the other way around (configuring higher target SNR thus forcing lower sync speed) did not work; that is why I tried configuring lower sync (thus forcing higher SNR), which eventually did work. I agree that having the 40/10 option at the lower BT (retail, openreach, never quite sure) level would have had the same effect (more permanently) on download, but it would have seriously compromised my upload.

Summary:
For anyone who cannot get or does not want more than 10 upload, the 40/10 option is the way to go.
For people who are happy with the PlusNet 40/20 and do use >10 upload, the configuration changes others helped me find are the way to go (till someone suggests better).

Edited by StephenTodd (Fri 30-Jan-15 11:15:15)

Plusnet doesn't have (officially) a currently orderable 40/10 option. Few will rule it out because of that .