Functional Description

700-701-100-02

 

 

Table 12. Loopbacks Selected at Front Panel Pushbuttons and Console Screens

LoopbackDescription

The two loopbacks that follow can be selected from the LOC and REM front-panel pushbuttons, the console screens, or the management unit interface.

LOC Pushbutton—Local

This is an analog loopback implemented in both HDSL transceivers, and enables a complete checkout

HDSL Loopback

of the local equipment by looping back data at the furthest point before the transmission media. The

 

HDSL link goes down as a result of this loopback, and is therefore not selectable from the remote unit

 

console screens.

REM Pushbutton—Remote

Data is transmitted across the HDSL link and looped back at the remote interface ports. The HDSL

Loopback

link must be up for this loopback to be available. With no HDSL link up, the REM button will not enable

 

any loopbacks.

The three loopbacks that follow are available exclusively from the console screens or management unit interface.

Local Interface Loopback

Data is looped back at the closest point in the local unit toward customer equipment. This loopback

 

is useful for verification of a proper connection at the local interface between your DTE and the local

 

HDSL card. The HDSL link is maintained during this loopback.

Local or Interface Loopback Away from the Local Equipment

Data is looped back at the local unit or remote unit back toward the remote DTE equipment. This is equivalent to pressing the REM button on the remote unit’s front panel, and is made available at the local console screen for ease of installation. The injected test data and loopback verification must still be performed at the remote unit site. Local equipment outputs an AIS for the duration of this test.

Remote Interface Away

Data is looped back at the remote unit toward the remote DTE equipment. This is available at the local

from the Local Equipment

console screen for the duration of this test. The injected test data and loopback verification must still

 

be performed at the remote unit site. Local equipment outputs an AIS for the duration of this test.

 

 

The following applies to LTU and NTU loopbacks:

•No inband loopback codes are recognized or generated.

•A remote HDSL loopback is not available from the local console screen as it causes the HDSL link to go down and requires user action at the remote unit to disengage the loopback.

20

August 9, 2002

UTU-701 and ETU-751 List 1