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[baresi]

I am on DSL here in Canada, been struggling with my DSL that hasn't been resolved and trying to get a technician to come in and check the wiring. At least the internal wiring is what the ISP and Bell phone company blame it on.

ST516 modem frequently drops with its internet light going off and then flashing, then DSL light flashing I guess trying to sync again. One of the things I have found is using DMT is that the error most often seen is 'Transmitted HEC' (link to most recent DMT screenshot below), is this a clue as to what the real issue is? The reason I am doubting a bit what the ISP says is that there have been days where my connection has been very good the it is followed by very poor days then back again. What can be wrong to account for the good days? Surely wiring and even error corrections can't "fix" themselves for a few days?

FWIW as far as I can tell things like weather or interference inside the house are not likely issues, I am keeping logs of times I see disconnects (I have also removed WRT54G to try without it with little difference) and there is nothing different from the days that my connection is good and days it's not. Have tried with different cables and jacks too.

Any help appreciated. Thanks.

http://img856.imageshack.us/img856/1839/dmt201203291615.png

[asbokid]

Not sure why you've only got the Bit Loading graph.  Where are the SNR and Line Atten graphs?

The waviness to the Bit Loading graph above 552kHz suggests an interference..  perhaps a bridge tap? The tap (or taps) can create reflections which are picked up as narrowband noise around specific harmonic frequencies, determined by the length of the tap.  For the affected sub-carriers using those frequencies, the reflection noise reduces the SNR for those bins to a sub-useable level. Consequently, the carriers remain un-utilised.  That can cause the waviness that we can see.  The bridge tap could be within your home, in the consumer wiring itself.

Equally, the cause of the noise could be from RF interference in your neighbourhood.  Do you have one of those enormous old-fashioned American refrigerators?  If so, do you want to sell it?

cheers, a

EDIT:  See http://www.jdsu.com/ProductLiterature/sctpsbridgedtap_an_tfs_tm_ae.pdf

[baresi]

Thanks for the detailed reply.

Might be the firmware (?) but the middle graph has never worked, have tried compatible DMT versions for the ST516. May be if there is another tool that works with ST516s? The other recent DMT screenshots I have I have not activated SNR monitor (bottom graph) but I went through older ones and most - not all - of the time it's a straight line with a few times dropping to minus side.

We do have a very old fridge, so that is a possible culprit too? There are just way too many variables...line quality, distance, internal appliances, etc. I am surprised DSL ever works

[asbokid]

Thanks for the detailed reply.

Might be the firmware (?) but the middle graph has never worked, have tried compatible DMT versions for the ST516. May be if there is another tool that works with ST516s? The other recent DMT screenshots I have I have not activated SNR monitor (bottom graph) but I went through older ones and most - not all - of the time it's a straight line with a few times dropping to minus side.

There seem to be several hardware and firmware versions for the ST516.  Some of them can definitely be used with DMT to plot the SNR and Line Attenuation graphs.  It's not clear which versions though!  Here's a DMT plot from an ST516 from dslreports.com to show it can be done. [1]   Maybe you could check the statistics through the telnet CLI interface on the modem, if it's enabled. [2]

The RCO - Relative Capacity Occupation - for your connection looks distinctly low at 45% for the downstream channel.  The RCO is the percentage ratio of available data rate vs line synchronisation rate. [2] [3]   And your sync rate, if DMT is correct, is 11,136Kb/sec.  Transmission overheads are typically 10%.. so you could expect to get ~10,000Kb/sec rather than 5055Kb/sec.

Maybe temporarily disconnect all home telephone wiring, and plug the modem in at the 'master socket', the point where the telco discharges its responsibilities.   Run DMT again, and see if the problem persists.   Then maybe try another modem, of a different make / chipset.

Good luck! Hope you get it sorted soon.

cheers, a

[1] http://www.dslreports.com/forum/remark,21723437
[2] http://www.dslreports.com/faq/6728
[3] http://www.kitz.co.uk/adsl/linestats.htm

[jeffbb]

Hi
What package are you on with a DS attenuation of 11db I would expect much higher Synch rate than your current 5500Kbps . The SNR margin of 28.5 db shows there is some cap in place .
If you can try
routerstats  if your router is compatible this will plot Synch,SNR margin and other graphs over any time frame rather than spot checks ,very good troubleshooting tool .
Regards Jeff

[baresi]

Thanks again guys. I will try to post more data (from the main socket) soon.

Other things though: none of the CLI methods work for me, I can login telnet but it doesn't look like that and - at least - I don't see options that would show stats. May be because mine is a Thomson ST516?

These are available when logged in

Code: [Select]

_{Administrator}=>help
Following commands are available :

help             : Displays this help information
menu             : Displays menu
?                : Displays this help information
exit             : Exits this shell.
..               : Exits group selection.
saveall          : Saves current configuration.
ping             : Send ICMP ECHO_REQUEST packets.
traceroute       : Send ICMP/UDP packets to trace the ip path.

Following command groups are available :

firewall        service         autopvc         connection      cwmp
dhcp            dns             dsd             dyndns          eth
adsl            atm             config          debug           env
expr            grp             hostmgr         ids             igmp
interface       ip              ipqos           label           language
mbus            memm            mlp             nat             ppp
pptp            script          snmp            sntp            software
system          systemlog       tls             upgrade         upnp
user
These version info are available in the modem GUI

Code: [Select]

Product Name: ST516
Serial Number: CP0838DT4EB
Software Release: 6.2.29.2
Software Variant: GE
Boot Loader Version: 1.0.6
Product Code: 3594263A
Board Name: BANT-V
My router is WRT54G, I don't think it works with routerstats or does it?

[asbokid]

Sorry. It's not a modem I've used.  Demon Internet did give me an ST585 some while ago, and it was rock solid in its reliability, but never really impressed on performance. The chipset in the ST516 (Broadcom BCM6338) is getting quite old now. Not that it's the cause of your problem, but newer ADSL chips could offer better performance, or greater stability.

The CLI Reference Guide for the ST516 (v.6) is here..

http://www.speedtouchturkiye.com/destek/ST546v6/guide/ST516-536-546_CLI.pdf

cheers, a

[baresi]

Thanks for your help and patience.

In the CLI reference there is lots of info available for "adsl info" but all I get is

Code: [Select]

Modemstate                   :  Up
xDSL Type                    :  ADSL2
Bandwidth (Down/Up - kbit/s) :  5055/797
Uptime (days hh:mm:ss)       :  0 days, 15:41:37
May be time for a new modem but I will give other tests a try first just in case.

[burakkucat]

Perhaps you could source a 2Wire 2700HG or 2701HG that is appropriate to Canada?

In your situation, I would see if I could get a 2Wire 2700HG-B (with AT&T firmware) from that country across the southern border. 

[baresi]

Perhaps you could source a 2Wire 2700HG or 2701HG that is appropriate to Canada?

In your situation, I would see if I could get a 2Wire 2700HG-B (with AT&T firmware) from that country across the southern border. 

Pretty sure they are not readily available as you allude to but will take a look. But in your opinion they are recommended modems?

[burakkucat]

In my opinion, they are good for "difficult" lines, yes. 

At The Cattery I have one 2700HG, two 2700HG-Bs, two 2700HGVs and two 2701HGV-Cs. Currently I am using one of the 2700HGVs for my connection.

[baresi]

Thanks burakkucat

It's so unbelievable that I am sure I missed something. I checked the demarc cabinet just inside the house (I see the cables and runs to the inside of the house) and box outside where the phone line comes in and there is no place for me to test the modem with a regular cable (no jack basically so I need tools to hock up wires to check). It's not like this house is ancient, it's 20 years old...I guess I will have to either learn it myself or get someone to do tests and set up a proper demarc point too.

I will be back sooner or later, hope you guys find the time to help again when I come back, thanks all