Line attenuation

M

Mikrouwel

Well-Known Member
Joined
Jun 11, 2011
Messages
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Location
Cape Town/Johannesburg
Hey Guys,

I was recently told by a telkom technician the the attenuation on your like must be below 50 for it to work properly and the fact that mine is 54 24/7 is why i get intermittent connectivity. He logged a fault for me and I got call after call from telkom saying my line is working perfectly and that my attenuation is 28 odd when I can see on my router its 54.

What do I do now?
 
Your ADSL modem (unless its a Siemens Gigaset one) should report 2 line attenuation values: 1 for downstream and 1 for upstream.
The downstream one should be roughly 2x as much as the upstream one with ADSL.

The line attenuation is mainly affected by the distance from your home to the DSLAM (which often reside inside the exchange). The attenuation is also a factor of the frequencies used to transmit the data, and this is why the attenuation of the upstream link is usually 1/2 of the downstream one, because the upstream link uses a lower frequency range than the downstream link.

The line attenuation values should remain fixed, unless you move house or to a different DSLAM.

The SNR margins can fluctuate quite a bit, but you want them to remain fixed and as high as possible. If your SNR margins fluctuate, then there is some kind of intermittent interference taking place that is negatively influencing your ADSL signal.

Lastly, 54dB downstream line attenuation is pretty high, and it would mean that you'll only be able to get like up to a 2Mbps connection stable. Anything faster than 1-2Mbps you may run into stability issues.
 
Thanks for the reply,

I am on a 2mb line atm and its anything but stable... :(

Should I contact telkom again?

Also my upstream noise is 29db
 
Yes
Call Telkom again. Try to reopen the previous call (they will not reopen it if it is 2 days since it was closed), or open a new one.
Keep calling every day telling them the line is unstable, and keep the call open as it will be escalated after a few days, hopefully to someone who can investigate the issue properly and ensure that the line quality problem is properly dealt with.
 
Your SNR margins are pretty good (above 10dB).

Do you have a telephone/alarm connected without a POTS filter perhaps? I see you have quite a few CRC errors on the upstream link. The upstream link's frequency range is in the lower end of the spectrum and also not too far away from the voice/telephone frequency range.
 
All the telephones and the alarm are connected with filters. I will however try replacing them since some of them are quite old.

Thanks again for the help guys :)
 
I tried just with the modem straight into the wall with nothing else connected and my attenuation decreased by 1db :/

So now do I just do what Electron1 suggested and nag the hell out of them?
 
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