Testing 152-388-100-02, Issue 2
42 June 6, 2000 H2TU-C-388 List 1
Manual Loopback Session
A manual loopback session allows you to select any one of the HiGain loopbacks listed in Table 15 on page 40
with the exception of SmartJack loopbacks, which can only be issued by inband commands.
Setting the Loopback Time-out Option
Before initiating a loopback session, verify that the Loopback Time-out parameter is set to the desired setting.
1 Use the MODE and SEL buttons as described in “Setting Options through MODE and SEL” on page 9.
(The Loopback Time-out parameter is also user-selectable from the System Settings screen when using a
maintenance terminal.)
2 Select the desired setting:
• NONE (time-out disabled)
• 20 minutes
• 60 minutes (default setting)
• 120 minutes
Activating Manual Loopback Mode
To initiate a manual loopback session:
1 Press both the MODE and SEL buttons on the front panel for at least 5 seconds. The following message
appears on the front-panel display:
MAN LPBK NLO?
2 Press SEL to activate NLOC. The display changes to MAN LPBK NLOC.
3 Press MODE to advance to the next available loopback:
• NRE? = NREM
• CRE? = CREM
• CLO? = CLOC
• COL? = dual loopback at H2TU-C.
• RUL? = dual loopback at H2TU-R.
With the exception of SmartJack, any of the HiGain loopbacks can be executed using the MODE
and SEL buttons.
When executing a manual loopback session using the MODE and SEL buttons:
• The next loopback option can be displayed by pressing the MODE button, however, the
previously activated loopback remains active until the SEL button is pressed, which
activates the new loopback.
• If neither button 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.
• If there is an active loopback, pressing the MODE and SEL buttons for 3 or more seconds
terminates any active loopback, ends the manual loopback session, and returns the display
to normal mode.