How to improve quality of a ADSL line?

To write this article I was inspired because of my home Internet connection.
I am using BeotelNet ADSL internet.

My Internet connection was interrupted every few hours and then ADSL started reconnecting again.

My ADSL modem was set up to choose ADSL Mode & Type automatically.

Then I configured ADSL Mode manually to ADSL2+ and Type to ANNEX A.
TP-LINK modem:
Default username and password is admin, unless you have changed it.
Advanced Setup > ADSL


Since i configured these settings, my Internet connection works for over 24h with no interruptions.


What is the catch?
Modem automatically choose between modulation what is best for your line. But Annex M has more quality requirements and that is why line drops.
ADSL ISP usually do not offer speed higher than 24MBPS for ADSL2+ (We are not talking about VDSL2+ here).
That is why all ISP require ANNEX A to be set up on modem when they are doing diagnostic of the line.
If you line is ISDN, then you have to use ANNEX M.

One more important thing is STATUS page:


SNR Margin – Signal-to-noise ratio (SNR) is defined as the power ratio between a signal (meaningful information) and the background noise (unwanted signal).

Line attenuation is a measure of how much the signal has degraded between the DSLAM and the modem. This is largely a function of the distance from the exchange. The lower the dB, the better for this measurement. Attenuation is logarithmic and each 3dB of attenuation halves the strength of the signal power received.

Data Rate: Maksimalna brzina koju trenutno ostvarajuete.

Max Rate: Maksimalna brzina koju vaša linija može ostvariti (ukoliko povećate paket da okvirno znate do koliko možete da ga povećate).

POWER: Snaga

CRC: CRC is Cable Read check. A high number means that there are some small cable breaks somewhere along your line to the exchange. Best to call Telkom and get them to sort it out for you.

If you are not having DSL speed higher than 5MBPS the best solutions is to set ADSL Mode to G.dmt so quality can be higher.
Up to 10 MBPS ADSL2 and over 10 mbps ADSL2+


If you have any advice put it in the comments.

About the author

Luka Paunovic

I am Linux System Administrator and student of Business economics at John Naisbitt University.
Love to blog and read blogs.