Kitz ADSL Broadband Information
adsl spacer  
Support this site
Home Broadband ISPs Tech Routers Wiki Forum
 
     
   Compare ISP   Rate your ISP
   Glossary   Glossary
 
Please login or register.

Login with username, password and session length
Advanced search  

News:

Author Topic: Bit Allocation Table - Speedtouch 585  (Read 4197 times)

Ian Goldby

  • Just arrived
  • *
  • Posts: 5
    • Home Page
Bit Allocation Table - Speedtouch 585
« on: January 30, 2009, 09:21:00 PM »

Does anyone know how I can see the bit allocation table on my Thomson Speedtouch 585 (v5.4.0.11).

Unfortunately I'm on a Mac and I can't get DMT Tool to work in CrossOver Office or Darwine.

There's probably something I can do in the CLI, but I can't make much sense of the manual.

Any advice would be much appreciated.
Logged

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 33879
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: Bit Allocation Table - Speedtouch 585
« Reply #1 on: January 30, 2009, 10:49:23 PM »

Im not sure for the 585v5.. and if its the same as the v6... if so the telnet command you need is

Code: [Select]
debug exec cmd='tdsl getData all'
Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker

Ian Goldby

  • Just arrived
  • *
  • Posts: 5
    • Home Page
Re: Bit Allocation Table - Speedtouch 585
« Reply #2 on: February 01, 2009, 08:41:52 AM »

Blimey! Pages of cryptic output.

Looks like it works then. Now to see if I can make any sense of it...

Cheers

Logged

Ian Goldby

  • Just arrived
  • *
  • Posts: 5
    • Home Page
Re: Bit Allocation Table - Speedtouch 585
« Reply #3 on: February 01, 2009, 08:45:42 PM »

OK, now I'm really confused.

I worked out how to get the SNR for each separate tone (all 252 of them) and plotted a graph at a time when the overall SNR margin was 8dB and I was getting lots of dropped packets.

Several hours later the connection recovered and I plotted a new graph of the SNR against tone (or bin).

The two graphs were identical.  :shrug2:

What I expected to see was a difference between the graphs that indicated which frequencies (or bins/tones) were getting overwhelmed with interference.

What's going on?

[attachment deleted by admin]
Logged

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 33879
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: Bit Allocation Table - Speedtouch 585
« Reply #4 on: February 01, 2009, 09:31:37 PM »

>> The two graphs were identical.

Its not unusual for the shape of the 2 graphs (SNR v bit loading) to follow exactly the same pattern - its supposed to work like that - the better the SNR, then the more bits that can be loaded per bin.

The connection may have deteriorated, and yes I would have expected at this point for bit loading to decrease (in line with the SNRM).  After recovery it wont change that much since the bits will probably stay were they are as long as there are sufficient bits overall to cope with the sync speed.  It would take a full resync/initialisation to recover and allocate a brand new BAT... although admittedly the true SNR value should have increased.

From your graph plot it looks like you are seeing several spats where interference is kicking in.. but mostly around bin 150 - therefore around the 650kHz frequency mark. 
Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker

Ian Goldby

  • Just arrived
  • *
  • Posts: 5
    • Home Page
Re: Bit Allocation Table - Speedtouch 585
« Reply #5 on: February 01, 2009, 09:53:18 PM »

Sorry, what I meant was that the graphs of SNR during and after the 'noise episode' were identical. I expected the SNR graph after the line recovered a bit to have less dips in it.

(I haven't actually tried plotting bit loading because I assumed it would follow the same shape as the SNR graph anyway.)
Logged

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 33879
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: Bit Allocation Table - Speedtouch 585
« Reply #6 on: February 01, 2009, 09:57:24 PM »

>> I expected the SNR graph after the line recovered a bit to have less dips in it.

Indeed you would expect it to do so, since it is supposed to be real time monitoring.
<< (  admittedly the true SNR value should have increased.)
Unfortunately I really dont have any idea why it hasnt  :(
Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker

Ian Goldby

  • Just arrived
  • *
  • Posts: 5
    • Home Page
Re: Bit Allocation Table - Speedtouch 585
« Reply #7 on: February 01, 2009, 10:03:36 PM »

There's another block of data labelled 'Noise Margin'. Perhaps I should have plotted that...   :hmm:

OK, done that. Now I need to wait for the connection to go bad again. (13.5 dB of SNR margin on a 3.5km line at 1Mbps at the moment. Woohoo!)
« Last Edit: February 01, 2009, 10:14:14 PM by Ian Goldby »
Logged

kitz

  • Administrator
  • Senior Kitizen
  • *
  • Posts: 33879
  • Trinity: Most guys do.
    • http://www.kitz.co.uk
Re: Bit Allocation Table - Speedtouch 585
« Reply #8 on: February 01, 2009, 11:05:28 PM »

For some examples how SNR Margin, true SNR and bit loading mirror each other see the graphs on the bottom of the DMT page.  The bottom graph shows a classic example of what happens after a line improvement and how the spikes invert mirror afterwards.

Blue is bit loading, Yellow is SNRM and grey is true SNR.
Logged
Please do not PM me with queries for broadband help as I may not be able to respond.
-----
How to get your router line stats :: ADSL Exchange Checker
 

anything