DQI
is displayed as a simple scale ranging from "0" to "10"
with "10" representing highest quality. The current DQI reading
is displayed in the upper right side of the screen and immediately below
is the lowest DQI reading measured since the DQI measurement mode was
entered. The most recent 180 seconds of measurement results are plotted
in a historical graph with each display pixel representing a second of
time with the right of the graph being most recent measurement. Typically
readings of 0 to 5 indicate that subscriber service is most likely being
adversely affected by the impairments. Readings of 6 or 7 indicate that
impairments are detected but are most likely corrected by FEC and interleaving.
Readings of 8 and higher are typically not detected by FEC BER.
To assure that DQI is only measuring issues on the HFC distribution
network, the meter should be placed in a stable physical state without
any movement or mechanical shock to either the meter or the test lead
connection.