ZyXEL Communications VES1724-56 User Manual page 364

Chapter 40 Loop Diagnostic
Table 173 Single Ended Line Test (continued)
LABEL
SELT Start
Calibrate
Loop Type
Loop length
Reflection
Delay
Error
Atn@180kHz
Atn@300kHz
FitError
Termination
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DESCRIPTION
Click SELT Start to start a single-end loop test.
Note: Connect the Telco-50 connector to the VDSL Line port, but the selected DSL port must
have an open loop. There cannot be a DSL device, phone, fax machine or other device
connected to the subscriber's end of the VDSL line.
The SELT takes at least fifteen seconds. To check the status of a SELT or look at the last SELT
result of a port, select the port number from the Port drop-down list box and click Show
Status. The results tell you what gauge of telephone wire is connected to the port and the
approximate length of the line.
Click Calibrate to reset the SELT parameters on the Switch to achieve high SELT accuracy.
Note: Make sure you disconnect the Telco-50 connector from the VDSL Line port before you
do calibration.
This field displays what gauge of telephone wire is connected to the port.
This field displays the distance from the Switch to the subscriber's location.
This field displays the index number of each reflection in a test. Only the first 4 reflection
results are displayed.
When you perform a SELT, the Switch sends a wideband signal and calculates the loop
information from the signal echoes (reflections).
Note: Only the reflection from the end of a line indicates proper information for your reference.
This field displays the estimated delays the Switch calculates from each reflection.
This field displays the estimated errors the Switch calculates from each reflection.
This field displays the estimated attenuation the Switch calculates for the band at 180kHz on
the line.
This field displays the estimated attenuation the Switch calculates for the band at 300kHz on
the line.
This field displays an indicator of the error in the attenuation fields.
This field displays the phase jump at the line termination. A value of 0 indicates a shortcut
termination. A value of 1 indicates an open termination.
VES1724-56 User's Guide