Finding Disturbers - JDS Uniphase HST-3000 User Manual

Finding disturbers

To run a SELT termination
1 On the right panel of the HST-3000, connect one end of
the test cable to the DSL connector, and the other end to
the line under test.
2 On the Summary results screen, press the SELT TERM.
soft key.
The modem is turned off, the line is terminated, and the
SELT message appears.
3 The far end technician can continue testing.
4 Press the DSL Start soft key to exit SELT mode.
The graphical displays can be useful tools for finding
disturbers. The graphs are pictorial representations of the bits
per tone (BPT), signal to noise ratio (SNR), H.log, or quiet line
noise (QLN). Using these graphs to locate interference is not
a precise method. However, this process can help you isolate
the frequency where the interference occurs. You can then
use that information to identify possible sources of interfer-
ence.
To find disturbers
1 After running the test, press the Display soft key and then
select Graphs.
2 Press the Graphs soft key.
NOTE:
The graphs only appear if you are connected to the line and
the modem has trained on the line.
3 Select View BPT graph.
HST-3000 xDSL Testing User's Guide
Chapter 2 DSL Testing
Finding disturbers
27