Understanding the output of DMT

I'm having intermittent problems with my broadband connection: every so
often (once or twice every few days). I've now started monitoring the
connection with DMT V8. The router is a Netgear DG834GT.

- noise margin drops by about 1 dB when it's normally rock steady +/- 0.1 dB

- lots of CRC errors, sometimes LOS (loss of sync) and occasionally a rise
in ES

- router loses ability to communicate with outside world; L8NC reveals that
router cannot be pinged from outside at these times

- DSL light flickers rapidly with no corresponding wireless or Ethernet
light activity

Unplugging the DSL cable for a few seconds is usually enough to rectify the
problem.


The SNR per tone graph looks normal and does not change when the problem
occurs. It shows values of between 29 and 55 dB with no gaps over the range
of tones from about 30 to 254 and jsut two tones where the SNR is slightly
below the adjacent values.

How much information about what's happening can be gleaned from the DMT
debug log: is it worth me posting a sample of the good and bad values in
this file in the hope that someone can interpret them.

The problem occurred a month or so ago and then seemed to go away, but it's
recently started up again. On the last occasion, my ISP said that the next
step was to report it for BT to investigate, but warned me that there *may*
be a charge of £150 (approx) from BT, so I'm keen to eliminate everything
else first.

The problem has been seen with the router connected to the master test
socket, though I normally use it on the end of a short BT-installed
extension. Line stats are very similar in either case.

Stats are:

Connection Speed 8128 kbps 448 kbps
Line Attenuation 8.0 db 4.5 db
Noise Margin 14.6 db 24.0 db


With the noise margin dropping to about 13.5 when the fault is seen. No
other stats change.

It does not seem to happen at an particular time of day, so there's no
obvious link to RFI when another electric appliance is turned on/off.


Is there a good explanation anywhere of the various ADSL terms like ES, SF,
LOS, LOF?

It happened to me, simply contact BT for a repair, they will charge you £200
+ vat I recollect, forward the bill to the landlady, who should in turn
claim off the installers - But bottom line, you have to pay BT first

As I hadnt payed the final bill to the installers, I simply gave them a copy
of the BT bill and deducted it from my cheque to them


"Mortimer" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> I'm having intermittent problems with my broadband connection: every so
> often (once or twice every few days). I've now started monitoring the
> connection with DMT V8. The router is a Netgear DG834GT.
>
> - noise margin drops by about 1 dB when it's normally rock steady +/- 0.1
> dB
>
> - lots of CRC errors, sometimes LOS (loss of sync) and occasionally a rise
> in ES
>
> - router loses ability to communicate with outside world; L8NC reveals
> that router cannot be pinged from outside at these times
>
> - DSL light flickers rapidly with no corresponding wireless or Ethernet
> light activity
>
> Unplugging the DSL cable for a few seconds is usually enough to rectify
> the problem.
>
>
> The SNR per tone graph looks normal and does not change when the problem
> occurs. It shows values of between 29 and 55 dB with no gaps over the
> range of tones from about 30 to 254 and jsut two tones where the SNR is
> slightly below the adjacent values.
>
> How much information about what's happening can be gleaned from the DMT
> debug log: is it worth me posting a sample of the good and bad values in
> this file in the hope that someone can interpret them.
>
> The problem occurred a month or so ago and then seemed to go away, but
> it's recently started up again. On the last occasion, my ISP said that the
> next step was to report it for BT to investigate, but warned me that there
> *may* be a charge of £150 (approx) from BT, so I'm keen to eliminate
> everything else first.
>
> The problem has been seen with the router connected to the master test
> socket, though I normally use it on the end of a short BT-installed
> extension. Line stats are very similar in either case.
>
> Stats are:
>
> Connection Speed 8128 kbps 448 kbps
> Line Attenuation 8.0 db 4.5 db
> Noise Margin 14.6 db 24.0 db
>
>
> With the noise margin dropping to about 13.5 when the fault is seen. No
> other stats change.
>
> It does not seem to happen at an particular time of day, so there's no
> obvious link to RFI when another electric appliance is turned on/off.
>
>
> Is there a good explanation anywhere of the various ADSL terms like ES,
> SF, LOS, LOF?
>