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[rwm32]

My nice new modem is just too keen to sync high.  I've got a pretty good line, but it's not quite good enough to hold 8000kbps with an acceptable error rate.  I'd like to get it sync'ing around 7400-7600kbps.

I'm trying to lift the SN margin slightly to achieve this, but DTM doesn't work with the TG585v7 firmware, and I can't seem to get any changes to stick when I use telnet and the CLI to make them.

I've ftp'd the user.ini file from the modem onto my PC, edited in the following line, uploaded it back onto the modem and rebooted, in the hope that modemoption1 set to x24 will set the SN margin to around 9dB:

[ adsl.ini ]
adsl config modemoption=240000002000000006000000000000000072

but the SN margin is still 6dB after restart/re-sync, the speed is still 7800-8000, and when I telnet back onto the modem, the CLI command 'adsl debug modemoptioninfo' gives

00:00:00:00:20:00:00:00:06:00:00:00:00:00:00:00:00:72

which is the factory default setting. What has happened to the change I made?

The TG585v7 CLI is supposedly the same as the latest ST585v6 (last of the SpeedTouches).

My line stats: ADSL Max, interleaved, d/s attenuation = 36dB, target SN margin from BT = 6dB, distance from exchange = c.2km.  I've had the TG585 hold 8000kbps for long enough to get a BRAS profile of 7000kbps (albeit briefly), but at that speed the FEC rate is astronomic, and the CRC rate is painfully high.

For the sake of completeness, I should add that I've got the modem's environment as clean as I can (plugged into master socket, ADSLNation filter + another filter in series, shielded modem cable, REIN sanitisation through relocation of noise sources) -- just awaiting delivery of a ferrite ring to put on the lead from the AC adaptor (and FWIW, the Thomson AC adaptor puts out hideous amounts of AM noise; fortunately it has a good long cord on the output side).  So I think it's unrealistic to hope for a stable, low-error sync at 8000.  Getting that speed at all with attenuation of 36dB is marginal anyway.

Sorry for the length of this post, and TIA for any help.

rwm32

[Astral]

My first thought was for you to request interleaving be enabled but I see it already is.

Do you hear noise on the phone line? I wonder if you have a "high open" fault.

[rwm32]

Thank you for the suggestion, but there is no noise on the phone -- and no obvious correspondence with the ADSL error rate and phone on- or off-hook. 

I don't usually fib, but the principle of covering all the bases, I did in fact report a (fictional) crackling on the voice line to BT a couple of weeks ago, so they have run a loop test recently.

The only thing I can think of that I haven't already mentioned is that we have two phone lines, one DSL enabled, one not.  The voice-only line is primarily for our alarm system, but it also gets used once or twice a week for a dial-up connection into the office -- yeah, I know, but they're switching to a BB/VPN solution in a couple of months -- and very infrequently for old-fashioned fax.  I've done a 17070 quiet line test on this line, as well as the ADSL one, and they are both good. 

I suppose it's possible that the alarm line could be interfering with the ADSL, though I don't have a clue what could be done about it if so. The lines physically come into the house together from the pole and are wired into a double socket. The ADSL line has only 2 wires connected in the socket; the alarm line has 4 -- but if I cut the extra 2 wires in that socket and the alarm connection goes wrong, I could be looking at call-out charges from BT and the alarm company...

So that takes me back to trying to raise the SN margin to sync consistently at a slightly lower rate.

Last night I forced a re-sync and by chance got 7680 -- the lowest I've experienced on this modem. After just over 10 hours CRC errors = 81, FEC errors = 341,103. The CRC errors were more or less linear, while the FEC errors ran at around 2000/hour, apart from two bursts, in each of which >100,000 clocked up in under 2 mins.  Errored seconds = 0.

By way of comparison, when the sync is at 8000, the CRC errors run into at least 100's per hour, while mega-bursts in the FEC count happen more frequently (though the base rate is still around 2000/hour).  Errored seconds go up in jumps of up to 10 or so.

Ooops - another lengthy post. Sorry!

[b4dger]

That's an interesting post rwm32.

I choose to turn my router (585v6) off every night and when I restart in the morning around 8.30 I notice that if I sync at around 4736 (which I did this morning) then my error count if likely to be very low throughout the day. But if I sync at over 4900 which sometimes happens then I see very high FECs especially as evening comes.

In the past I had looked at editing the modemoption string directly as you had tried - but I wasn't as brave as you and only did research and asked questions not wanting to 'upset' my sensitive exchange! The conclusion I came to was that from firmwares that don't allow the modemoption to be tweaked via telnet or DMT the string seems to be redundant.

Even when I rack up loads of FECs after a high sync I haven't lost sync but don't want the DLM to increase my target SNR if it thinks things are getting unstable. So what I sometimes do is re-sync  around 3pm when the SNRM is naturally lower which will give me a lower sync with less errors being recorded - but all still within the same IP Profile.

One option for you would be to re-sync later in the day which should mean a slightly lower sync. Then if you are the type of user that leaves their router on 24/7 you should be fine until you have to re-start.

When I was looking into this last year, I remember finding someone (on a Zen forum I think) who had a router (non-Thomson) that they could use a CLI command to 'restrict the maximum data rate' which had the desired affect for them and is what I was trying to find. If I could 'force' my router to sync at no more than 4736 my IP Profile would be safe and my error rate low - I guess this is what you are after as well.

I believe your ISP can also 'limit' adsl max but I don't know much about this and how much control they have - they might come in and force you down to 2Mb! Don't know if anyone else here knows what control providers have?

In an ideal world I would put a tweakable firmware on my router - increase the target SNR 1db and look at the modemoption string to see what it was set to. Then go back to the later non-tweakable firmware and edit the user.ini so the modemoption is the same as the tweaked version and see if it takes effect or if the string is ignored. But as adsl max is far too sensitive I don't want to risk messing everything up!

Let us know how you get on - especially if you find a 'maximum data rate' type command...

[Azzaka]

Thank you for the suggestion, but there is no noise on the phone -- and no obvious correspondence with the ADSL error rate and phone on- or off-hook. 

I don't usually fib, but the principle of covering all the bases, I did in fact report a (fictional) crackling on the voice line to BT a couple of weeks ago, so they have run a loop test recently.

The only thing I can think of that I haven't already mentioned is that we have two phone lines, one DSL enabled, one not.  The voice-only line is primarily for our alarm system, but it also gets used once or twice a week for a dial-up connection into the office -- yeah, I know, but they're switching to a BB/VPN solution in a couple of months -- and very infrequently for old-fashioned fax.  I've done a 17070 quiet line test on this line, as well as the ADSL one, and they are both good. 

I suppose it's possible that the alarm line could be interfering with the ADSL, though I don't have a clue what could be done about it if so. The lines physically come into the house together from the pole and are wired into a double socket. The ADSL line has only 2 wires connected in the socket; the alarm line has 4 -- but if I cut the extra 2 wires in that socket and the alarm connection goes wrong, I could be looking at call-out charges from BT and the alarm company...

So that takes me back to trying to raise the SN margin to sync consistently at a slightly lower rate.

Last night I forced a re-sync and by chance got 7680 -- the lowest I've experienced on this modem. After just over 10 hours CRC errors = 81, FEC errors = 341,103. The CRC errors were more or less linear, while the FEC errors ran at around 2000/hour, apart from two bursts, in each of which >100,000 clocked up in under 2 mins.  Errored seconds = 0.

By way of comparison, when the sync is at 8000, the CRC errors run into at least 100's per hour, while mega-bursts in the FEC count happen more frequently (though the base rate is still around 2000/hour).  Errored seconds go up in jumps of up to 10 or so.

Ooops - another lengthy post. Sorry!

rwm32 do me a favour and leave the modem for 72hrs. This will give rambo time to set the line for the new modem. Sometimes by changing the profile on the modem it can have issues with the BT servers.

Also make sure that when running the wizard you remove the password, and if you are using the cli the you type: saveall

before you exit.

[rwm32]

Many thanks for your responses.

...
In the past I had looked at editing the modemoption string directly as you had tried - but I wasn't as brave as you and only did research and asked questions not wanting to 'upset' my sensitive exchange! The conclusion I came to was that from firmwares that don't allow the modemoption to be tweaked via telnet or DMT the string seems to be redundant.

...
When I was looking into this last year, I remember finding someone (on a Zen forum I think) who had a router (non-Thomson) that they could use a CLI command to 'restrict the maximum data rate' which had the desired affect for them and is what I was trying to find. If I could 'force' my router to sync at no more than 4736 my IP Profile would be safe and my error rate low - I guess this is what you are after as well.

Interesting.  I'm wondering whether what I have to do to get 'modemoption' changes to stick is use the 'upgrade' CLI command to load my modified user.ini file.  The TG585 firmware is buggy -- 'restoring' a saved configuration file simply results in a return to factory defaults, so that's no good.  As I posted, I tried ftp'ing a modified user.ini onto the modem and rebooting, but downloading it again after the restart shows that the mods have disappeared.

I haven't come across anything remotely resembling a 'max sync limit' command in my grapplings with the TG585v7 CLI "reference manual", however -- and as you surmise, I don't want to risk getting a 2meg limit slapped on by an over-enthusiastic CS agent from the ISP!

rwm32 do me a favour and leave the modem for 72hrs. This will give rambo time to set the line for the new modem. Sometimes by changing the profile on the modem it can have issues with the BT servers.

Also make sure that when running the wizard you remove the password, and if you are using the cli the you type: saveall

before you exit.

Yes, I'll leave it alone as you suggest, tho' my itchy fingers now want to try 'upgrade' as mentioned above....
I'm probably being obtuse, but I'm not too sure what you mean by removing the password when running the wizard -- should I simply take the password off the Administrator account? 
I did remember to 'saveall'; it triggered a re-sync, so I know it registered -- but still no dice.

thanks again
rwm32

[Azzaka]

... Yes, I'll leave it alone as you suggest, tho' my itchy fingers now want to try 'upgrade' as mentioned above....
I'm probably being obtuse, but I'm not too sure what you mean by removing the password when running the wizard -- should I simply take the password off the Administrator account?  ...

If you run the setup wizard which is advisable, it asks you for a username and password. By default the wizard sets the password to the serial number of the modem. You should remove the password and then try the DMT Tool. But again i do suggest you leave it for a few days to settle.

If you don't use the wizard i have seen some issues where by the modem will drop the connection periodically due to a session timeout.

[b4dger]

Azzaka,
As you are an ISP rep, are you able to say if you can 'limit' a users connection speed to a precise figure?
TIA...

[rwm32]

Yes, thanks Azzaka.  That makes it clear. I hadn't appreciated the 'session timeout' danger of not using the setup wizard -- but fortunately I did in fact use it.

Sadly, DMT won't run on with 7.4.2.6 firmware on the TG585v7... it logs in OK, recognises the firmware rev, puts up a message to say it doesn't like it, then exits. Ho hum.

[rwm32]

Update: after another night at 7680, the error count still looks good: CRC = 265, FEC = 417,012, uptime just over 34 hours.

I've graphed the bitloading info off the router, in the hope that those with more understanding of these things (i.e. almost everybody) might comment on whether I'm right in thinking this looks OK, with no obvious problems.
TIA
rwm32

Edit:  Have just discovered STMT, which would of course have given me the same graph without any of the hassle... Doh!

[attachment deleted by admin]

[rwm32]

For interest.

Slow start to the working day today....  so I stumbled across this thread on the Whirlpool forum, which makes me think that I may be barking up a gumtree in trying to set the modemoption registers.

[b4dger]

If you are reading that like me, then that's what I meant earlier when I said I think the later non-tweakable firmwares may have made modemoptions reduntant...

Or are you pointing something else out?

[rwm32]

Sorry for any confusion, b4dger -- I was more focused on getting the Oz flavour with 'gumtree' than being clear...

I should have said that the post on W'pool reinforced your view that modemoption doesn't do anything in later firmwares.

While breaking off to write this post, I notice that my line re-sync'd itself up to 8000 (from 7680) just under 2 hours ago -- completely unbidden and without any PPP disconnect. SN margin at the time was steady on 6.5dB; it's now steady on 8dB, with remarkably few errors.  Have to wait and see what happens this evening -- but I'm expecting the error rate to soar...

[Azzaka]

Azzaka,
As you are an ISP rep, are you able to say if you can 'limit' a users connection speed to a precise figure?
TIA...

Hi Bud,

Depending on the ISP, they can request that the SNR is set to a certain value which will increase or decrease the Sync speed accordingly. One thing to note however is that the DLM should set this according to your line and also enable interleaving if needed. Hence I suggested that he leave the line for a few days.

Leo

[b4dger]

Hi Azzaka,
No I didn't mean setting a target SNR, I meant having a 'speed cap' put on your connection.

I know ISPs can limit ADSL MAX but I don't know how much control they have - thought you would know...