User guide

Controlling and Provisioning Network Devices Port Management (non-iMAP Devices)
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AlliedView NMS Administration Guide
• H(f) Imaginary - The imaginary component of the characteristic function.
• H(f) Real - The real component of the characteristic function.
• H(f) Amplitude - The amplitude of the characteristic function. This is computed from the real and imaginary components.
Amp = sqrt( r*r + i*i) where r is the real component and i the imaginary component.
• H(f) Phase - The phase of the characteristic function. This is computed from the real and imaginary components. Phase =
atan( i/r ) where r is the real component and i the imaginary component.
5.7.4 Single-End Line Testing (SELT)
5.7.4.1 Overview of SELT
SELT is a method for testing a DSL loop that is not terminated at the CPE. These tests provide for the loop information on
the length, the presence of open or short circuits, and estimates of pre-service capacity.
SELT testing is usually done in the following scenarios:
• Pre-CPE Installation - The loop exists, but not at the CPE. SELT can test the line for physical bridge and loop taps.
• Pre-CPE Activation - SELT can characterize the loop and measure loop noise. The information can be used to determine
maximum rates.
• Post Activation - If there is a problem, the characterization of the loop can be compared to the results of the pre-CPE
activation to see if there are any changes.
This feature works with the xDSL family (ADSL24A, ADSL24B, ADSL24SA, ADSL24AE, ADSL48A, and ADSL48B) of cards.
(VDSL cards will be supported in a future release.)
SELT sessions are limited to a single session at a time due to the amount of time (up to four minutes) each test can take to
complete and the resources needed to execute the test.
For accurate results, loops up to 9000 feet can be tested. Using the FULL options allows loops up to 12,000 feet can be
tested. Limits are as follows:
Annex B support is limited to 24 AWG loops. 26 AWG wiring is not supported and will produce erroneous results
The port/interface to be tested must be in operationally down: UP-DN-Failed. The state life-cycle for the port/interface
under test will be: UP-DN-Failed to start the test, UP-DN-In Test for the duration of the test and will be transitioned back
to UP-DN-Failed once testing has completed.
Refer to the iMAP User Guide for details on SELT testing.
5.7.4.2 Accessing SELT
From the Port Management application select an active ADSL port one of the supported card types. Select the ADSL
Configuration tab, then the Diagnostics tab. If the tab is not present then the port does not support SELT. Then select the
SELT tab, as shown in the following figure. If there is existing data from a previous SELT the fields are populated and the
SELT Graph tab will be active. If there was no previous SELT the SELT Graph tab will be inactive and grayed out.
To run SELT, select the Run SELT Test button. A panel appears with the options for the test. Refer to the following figure.