VC-400LT/RT+ VDSL2 CO&CPE Router MANUAL Ver.B3
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Figure 6.2.4 Display of SNR per Carrier
6.2.5 BitsGraphs
When VC-400LT link with VC-400RT+ , this graph will show the bits value for each tone.
Figure 6.2.5 Display Bits Per Tone Graph
Regarding the describe of "tone graph"(Only reference):
"If slow service is indicated, technicians can look at the bits per tone measurement. Dips in the bit
per tone graph indicate interference. Checking the frequency of the interference often makes it
possible to identify its cause. The accompanying chart shows the frequencies associated with
common interference sources, such as T1,E1 and HDSL. If the bits per tone are taking a hit and it is
determined that noise is not the cause, then the cause could be a DC fault, such as a bridge tap or
a wet section. Very low or nonexistent bits per tone in the high frequency band indicate the
presence of a long loop. If there is a major dip in the bits-per-tone graph but the noise
power-per-tone graph does not show any abnormalities, the most likely troubles are bridged taps or