LTPH-UM-1049-02, Issue 2 Testing
H2TU-C-319 List 4E January 9, 2002 57

SmartJack Loopback Commands

The HiGain HDSL2 SmartJack (SMJK) Loopback (LPBK) commands allow you to use in-band, out-of-band, and
universal codes to initiate and terminate loopback testing of the HiGain HDSL2 circuit. (See SmartJack Test
Procedure on page64 for additional info rmation.)
MANUAL LOOPBACK SESSION
A manual loopback session allows you to select any one of the HiGain HDSL2 loopbacks listed in Table22 on
page56.

Setting the Loopback Time-Out Option

Before initiating a loopback session, verify that the Loopback/MTA Time-out parameter is set to the desired
setting.
1Use the MODE and LBK pushbuttons as described in Setting Options through MODE and LBK on page10.
The Loopback Time-out parameter is also user-selectable from the System Settings screen when using a
maintenance terminal.
2Select the desired setting:
NONE (time-out disabled)
20 minutes
60 minutes
120 minutes (default setting)

Activating Manual Loopback Mode

To initiate a manual loopback session:
1Press both the MODE and LBK pushbuttons on the front panel for at least 3 seconds. The following message
appears on the front-panel display:
MAN LPBK NLO?
With the exception of SmartJack, any of the HiGain HDSL2 loopbacks can be executed using the
MODE and LBK pushbuttons.
When executing a manual loopback session using the MODE and LBK pushbuttons:
The next loopback option can be displayed by pressing the MODE pushbutton, however, the
previously activated loopback remains active until the LBK pushbutton is pressed, which
activates the new loopback.
If neither pushbutton is pressed for a period of 30 seconds and no loopback is in effect, the
manual loopback session terminates and the display returns to normal mode.
If any loopback is in effect, the 30-second time-out is inhibited. The active loopback and the
manual loopback session continue until the loopback times out in accordance with the LBTO
setting.
Only the SMJK loopback can exist with other network loopbacks at any given time.
If there is an active loopback, pressing the MODE and LBK pushbuttons for 3 or more
seconds terminates any active loopback, ends the manual loopback session and returns the
display to normal mode.