Allied Telesis AT-iMG606BD Especificaciones descargar pdf (Pagina 441)

100

101

12. Port Management - non-iMAP Devices Single-End Line Testing (SELT)

432

AlliedView NMS Administration Guide

12.3.8 Graphed Parameters

• Subcarriers - The same values are available for both upstream and downstream directions. Depending on the type of

port and actual mode of operation different subcarrier counts are used. The following table describes the possible values

• Bit Loading - Bits allocated per sub channel. Range is 0 to 15.

• Gain - Range is 0 - 4093/512.

• Quiet Line Noise - Noise on quite line. Range is -150 to -23 db/MHz.

• Signal/Noise Margin - The signal-to-noise ratio margin per band is the maximum increase in dB of the noise power

received at the xTU-R, such that the BER requirements are met for all bearer channels. The range is from -64 dB to +63

dB with 0.1 dB steps.

• Hlog(f) - The log of the characteristic function

• 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.

12.4 Single-End Line Testing (SELT)

12.4.1 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.

TABLE 12-3 Values for Subcarriers

Card Types Actual Standard Actual Annex Upstream Carriers Downstream Carriers

VDSL24A, VDSL24B 512 512

ADSL24A/B, ADSL24AE

ADSL48A, ADSL48B,

ADSL2, ADSL2M ANNEXB,

ANNEXM

64 256

others 32 256

ADSL2+

ADSL2+M

ANNEXB,

ANNEXM

64 512

32 512

1 2 ... 436 437 438 439 440 441 442 443 444 445 446 ... 994 995

Comentarios a estos manuales

Sin comentarios

Allied Telesis AT-iMG606BD Especificaciones Pagina 441

Comentarios a estos manuales

Relacionado con productos y manuales para Gateways / Controladores Allied Telesis AT-iMG606BD