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Message 1 of 22

Output power on router

i have just looked some old router stats i kept and realised that my output power has dropped and speed with it.


Heres three examples:



I have was just wondering if there is a way to increase the output power either myself or can BT do it?

So i can check if it what is effecting it?


Correct me if I'm wrong line output power is something i don't know anything about.


Thanks for your time, Rob.


Edit: looking at my line stats i should be getting between 3-5 Mbps ( i know there are lots of factors that effect line speed but i should be getting more then 1.4 Mbps surely)

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Message 2 of 22

Re: Output power on router

Power is set during the negotiation process between the router and the dslam/msan.


The line speed negotiation is agreed according to line attenuation and SNR margin, to sustain a stable connection.

The power levels are the result of the line speed negotiation.


If you have seen varying levels of power, it's because your router has been synching at various speeds, and follows that for some reason, the connection is not as stable as it should be ....  or something has changed on the line characteristics..... and it's usually noise level, but can be a line fault, which often shows up as a higher attenuation, especially if it's a high resistance fault from a poor connection, or bad joint.


If it's an element of noise then it has to be eradicated to get back to the original configuration.

Or if it was a temporary noise event, out of your control and has now passed, a re-sync should put it right.


It always "useful" to get your line stats and keep a copy when the line is good, as when and if it erodes, you have a guide...  😉

And clearly your best set is your April set, as at 49db loop loss, you should be looking for IP4000 at target 6dbSNRm.


What is your IP profille showing now?


You can get it from BT's speedtest :

Message 3 of 22

Re: Output power on router

ok thanks for clearing that up. I thought i remembered some 3rd party firmware you could adjust it with thats all.


The problem is the that April figure only lasted for 2-3 days before being reset. Its not the only time its 'randomly' jumped that like that but it never stays at those figures.


Heres the test results:


 Download speedachieved during the test was - 927 Kbps
 For your connection, the acceptable range of speeds is 200-1000 Kbps.
 Additional Information:
 Your DSL Connection Rate :1408 Kbps(DOWN-STREAM), 448 Kbps(UP-STREAM)
 IP Profile for your line is - 1000 Kbps



edit: i forgot to say i have been in this property for a bit over a year and the best stable connection i have had is 1856 kbps with 1500 line profile. That lasted for about 3-5 months.

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Message 4 of 22

Re: Output power on router

You can get 3rd party firmware for certain routers, to force SNR negotiation with the dslam, but it's only really useful if you have an excess of noise margin, and negotiating a 6db margin would entail a higher sync speed.

Your margin seems to be steady around 6db, which would suggest it's a goodish line.

What's a little strange is the lack of decent sync speed.


What exchange are you on?

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Message 5 of 22

Re: Output power on router

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Message 6 of 22

Re: Output power on router

Cadnam exchange is showing virtual paths as green, so no major backhaul problems, however it also shows BT have advised that no current planned date for WBC on 21CN exists, which maybe implies it's a minor or semi-rural exchange??

If it is the case it may be well subscribed, or even highly subscribed.


Is this the case?


Try and post a full set of stats with errors for your router..


This will tell you how :


Be good if it was a connection that had been running a while ...

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Message 7 of 22

Re: Output power on router

Sorry to but in..Rob_

Roger...those minor and semi-rural exchanges...will they never get 21cn?

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Message 8 of 22

Re: Output power on router

The rumour is .... when Nelson gets his eye back...   I'm not holding my breath atm  Smiley Sad

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Message 9 of 22

Re: Output power on router

i guess it might be a semi rural exchange as  its serves 1,811 residential premises 247 non-residential premises.


Hmm i swear it said it would be updated on the 31 march 2011 last time i checked weird... maybe I'm imagining it.


Here are my full stats as of now:


Connection information

Line stateConnected
Connection time2 days, 3:08:34
Downstream1,408 Kbps
Upstream448 Kbps


ADSL settings

ModulationITU-T G.992.1
Latency typeInterleaved
Noise margin (Down/Up)6.4 dB / 21.0 dB
Line attenuation (Down/Up)49.0 dB / 27.0 dB
Output power (Down/Up)15.8 dBm / 11.9 dBm
Loss of Framing (Local)0
Loss of Signal (Local)0
Loss of Power (Local)0
FEC Errors (Down/Up)70141345 / 12
CRC Errors (Down/Up)222 / 2147480000
HEC Errors (Down/Up)nil / 8
Error Seconds (Local)224
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Message 10 of 22

Re: Output power on router

With 49dB attenuation and 6dB snr you should be syncing at around 4500kps


@ Roger...LOL

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