The following information is given as a guide
only and you make any changes at your own risk.
Version 8 of the DMT tool works for the following routers:
Broadcom Routers - BCM 6338/6348/6358 adslctl tool
Belkin 7633, BT Voyager 210/2091/2100/2110,
D-link 2640B, DSL-2740B
WAG54GS, WRT54G 4.0
Netgear DG834GT/DG834NB/DG834PNB, Netgear DG834G v4 only (need to also enter debug mode for the Netgears)
Siemens SL2-141-I/SLI-5300-I/CL-110-I, Speedtouch 716g,
500V/W500V, T-Sinus 1054 DSL,
US Robotics 9107/9108/Ndx 9113,
The DMT Tool can be downloaded from http://dmt.mhilfe.de/ -
you need v8.
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 192.168.1.1)
- Insert your router login and password (default = admin, admin)
- 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.
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
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 SNR with
100% being your existing the BT set figure.
The slider is not
entirely accurate, and because each line is different then
you will have to experiment.
But as a guide:-
|Default Target SNR
||New Target SNR
||Slider value %