Operational data report : near end (Downstream)
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Attainable line rate : 7516 kbit/sec Maximum theoretical download rate
Attainable Atm rate : 7040 kbit/sec Maximum actual download rate before TCP overhead
Used line rate : 3400 kbit/sec Current theoretical download rate
Fast used Atm rate : 3008 kbit/sec Current actual fastpath download rate before TCP overhead. If this number is zero, please see the next line.
Interleaved used Atm rate : 0 kbits/sec Current actual interleaved download rate before TCP overhead. If you see a number other than zero here, your line is interleaved.
Rel. capacity occupation : 45 Percentage of line capacity used. If this number is above 78%, your line in its current state does not qualify for any speed upgrades.
Noise Margin : 17 dB This is a measure of how good your data signal is relative to the noise on the line. This should be a high number and in any case no lower than around 6 dB. If it's this low you could find the modem gets data errors or even sync problems.
Line attenuation : 42 dB Measures how much signal loss there is on the line - this should be a low number and in any case should be no more than around 60-65 dB.
Output Power : 15 dBm Indicates how hard the modem is working to maintain the link. High numbers (around 19 or above) can indicate possible problems.

Explanations for upstream data is the same as above.

Any of these numbers near or at the limits described can cause the modem to lose sync and/or have high error rates resulting in poor internet performance. This is usually due to poor cabling, interference, or a line which is near or at the distance limit of where ISP can still provide ADSL from the DSLAM.