The following information is given as a guide
only and you make any changes at your own risk.
Version 7 of the DMT tool works for the following routers:
Speedtouch 510v6, 516, 536, 546, 576, 585, 608, 706, 716, 780
If you have the Speedtouch 716g then you need DMTv8
Please note that in firmware versions 6.2+ Thomson have removed the ability to access some features after complaints from a UK ISP. Therefore all sections of DMT may not be available -in particular the SNR tweak.
Firmware version 220.127.116.11 is that last version that the SNR tweak will work with. - Download
Various firmware versions for the ST585v6 are also available for download from chrysalisnet.org
Later versions of the ST routers (including the TG585v7) may display Bit loading channels, but you will not be able to SNR tweak. To do this, before you connect DMT to your router, From Special >> Misc.options >> Firmware specific >> tick "allow untested firmware versions".
The DMT Tool can be downloaded from http://dmt.mhilfe.de/ -
you need v7.
site is German but when you install DMT you have the option to select
A translation of the page can be viewed here.
- Download and unzip into a folder.
- Click DMT.exe to start the program.
- Select "English"
- Select "Annex A"
- Insert your routers IP address (normally 192.168.1.254)
- Insert your router login and password (default = Administrator, password is left blank)
- Click "Connect".
Your Line stats
DMT shows you your current line stats from your router. With adsl
the figures we are normally the most interested in are the first
3 downstream figures.
- Bit rate - Your sync or connection speed.
- Attenuation - reduction in signal strength quality and directly
related to the length of your line. The lower the
figure the better the line. This figure
should stay static.
- SNRM - Signal to Noise Ratio Margin. This figure is subject
to fluctuations of Noise. The higher your SNR Margin, the better
the signal strength to background noise.
- tx pwr - transmit power
- RCO - Routers estimation of maximum achievable sync speed
on adsl expressed as a %.
- ADSL fast path - Will either be fast or interleaved, depending
if interleaving is switched
on or not.
Line Stats and Condition
DMT connects to your router and will show you other information about your line and the router, such as the number of line errors and router performance.
Show which range of frequencies are being used by your router and the strength of the signal for that particular carrier bin.
Tone no is the carrier bin used by that particular frequency. Bottom figure shows the frequency range in kHz. The above diagram shows healthy stats. Dips can help identify areas where there may be RF interference. Bin 64 is a pilot-tone and is normal on adslv1.
Your SNR Margin plays a big part in the condition of your line
particularly with maxdsl/radsl. If your SNR Margin drops too low
then your connection starts to become unstable. You will likely
see CRC etc errors and errored seconds and your connection may
drop. You can monitor your SNR Margin over a period of time using
DMT tool, and the graph will show any fluctuations in your SNR
DMTv7 has a 2 sets of figures that it can show you for SNR Monitoring. When first turned on it will show you the SNR fluctuation for each individual channel (bin). You can also get it to record the overall SNR fluctuation over a period of time. To turn this on simply set the monitor interval (default is 8 seconds) and press the Start Button.
The above screen shot shows both the channel fluctuations, and you can see on the left DMT starting to record overcall SNR fluctuation. If both records are confusing and you only want the overall figures simply untick the snrft checkbox.
By default the SNR monitoring is over a 60 minute period but you can change this setting in the drop down box in Special > Misc.Options from the top toolbar.
For more information on SNR see my line
Changing your Target SNR.
Each time you connect, your router will try and sync at the highest
speed it can whilst still allowing a safe margin of SNR to allow
for normal noise fluctuations that occur over the course of the
day. The default Target SNR is 6dB, but the DLM at the exchange
can also set your Target SNR to 6, 9, 12 or 15dB.
Possibly the easiest way of finding out the Target SNR set on
your line is checking your SNR Margin immediately after a resync.
Generally speaking if your SNR Margin is 6dB then your Target SNR
is likely to be 6dB.
Please note that this method is not fool-proof because lines that
have a good overhead of SNR and are able to sync at the full 8128
kbps (or 7616 with Interleaving), will show a higher figure anyhow.
Sometimes your Target SNR may not be perhaps quite the best for
your line and you may wish to change this yourself, by either increasing
your Target SNR to improve stability of your line. Or it may be
that your SNR Margin is normally very stable and you want to see
if by bringing your Target SNR down you can perhaps get a bit more
Enabling the Hidden 5th Tab to change
your Target SNR
- From the top toolbar select
- A new window will open Misc. Options/Settings
- From Expert Settings -
- Tick the checkbox "unlock experimental area Panel/Last
- Click the "Save/Close" Button
The slider allows you to adjust your Target SNR within a minimum and maximum figure.
The slider is supposedly to the scale of 10 notches = 1dB of SNR.
As a guide you should increase the Target SNR for a lower sync and more stability, and decrease if your line is stable and you are looking for higher speeds.
To apply the setting click the top button and your router will resync to the exchange. The "Save Settings" button saves your preferred setting to the Flash memory of your router, so its recommended you only do this once you are happy with your settings.
"set/save default" returns settings to the way they were before you used DMT.