In-Band Loopback Sessions; General Troubleshooting Tips; Gnlb Test Procedures - ADC HiGain H2TU-C-231 Manual

Testing
3 Press MODE to advance to the next available loopback:
•
NRE? = NREM
•
CRE? = CREM
•
CLO? = CLOC
4 Press SEL to activate the selected loopback. The previous loopback is terminated.
Once a loopback is selected and activated, the loopback stays active until it times out (based on the LBTO setting).
When a loopback times out, the display then returns to the normal display mode.
You can terminate loopbacks manually and exit the MAN LPBK mode by simultaneously pressing the MODE and
SEL pushbuttons for 3 or more seconds. If no loopback is active, the MAN LPBK mode automatically terminates
after 30 seconds.
All loopbacks can be initiated by in-band commands in the DS1 payload or by a command from the HiGain
HDSL2 system (front-panel pushbuttons or maintenance screen selections). Therefore, whenever a loopback is
active, the method by which it was activated is indicated in the loopback and status information (Monitor screen)
by the annotation HG or PL adjacent to the identified loopback. For example, NREM-HG indicates that the
loopback was initiated by the HiGain HDSL2 system.
SMJK loopback commands are only activated by in-band commands.
I -B L
N AND OOPBACK
The following sections provide step-by-step test procedures for verifying the integrity of the HDSL2 channels at
every module location as well as the DS1 channels to the customer and the local DSX-1 interface.

General Troubleshooting Tips

If trouble is encountered on the DSX-1 interface of the H2TU-C, verify that the:
•
H2TU-C is making a positive connection with its mounting-assembly (shelf) connector.
•
H2TU-C internal equalizer is set to the correct distance range per
be set to the distance from the DSX-1 to the shelf.
The transmit and receive DSX-1 ports have splitting access jacks and miniature 210-series, bridging jacks as
shown in Figure 1 on page
LINE jacks splits the IN and OUT and creates metallic loopbacks towards both the DSX-1 and the H2TU-C-231.
If separate plugs are inserted into both LINE jacks with the other end disconnected, the BRG jacks can be used to
send and receive test patterns towards the DSX-1.

GNLB Test Procedures

Figure 28 on page 51
GNLB commands shown. Refer to
To perform the GNLB loopback test procedure:
1 Have the CO tester send the NREM (3-in-7) in-band loopup code for 5 seconds. You should be able to observe
the NREM message on the front-panel display. (The Status LED on the front panel should be green, and the
loopback mode should also be identified on the Monitor screen.)
2 Have the CO tester transmit a DS1 test signal towards the H2TU-C and verify that the returned (looped) signal
to the test set is error-free.
50
S
ESSIONS
3. Connecting one cable between the two BRG jacks and another between the two
is a graphical representation of the various loopback configurations with the associated
Table 22 on page 48
September 28, 2001
Table 6 on page
for a description of these commands.
LTPH-TP-1034-01, Issue 1
18. All equalizers should
H2TU-C-231 List 4E