ADC HiGain H2TU-C-319 List 4E - Manual (Page 67)

LTPH-UM-1049-02, Issue 2 Testing
H2TU-C-319 List 4E January 9, 2002 59
You can also manually terminate the MTA state and exit the MAN LPBK mode by simultaneously pressing the
MODE and LBK pushbuttons for 3 or more seconds. If no loopback or MTA is active, the MAN LPBK mode
automatically terminates after 30 seconds.
IN - BAND L OOPBACK S ESSIONS
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 interfaces of the H2TU-C, verify that the:
• H2TU-C is making a positive connection with its shelf connector.
• H2TU-C internal equalizer is set to the correct distance range, as shown in Table 5 on page 18 . All equalizers
should 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 3 . Connecting one cable between the two bridging jacks and another between the two
LINE jacks splits the IN and OUT and creates metallic loopbacks toward both the DSX-1 and the H2TU-C. 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 toward the DSX-1. The AUX DSX-1 port has no resident test jack access.
GNLB Test Procedures
Figure 32 on page 60 is a graphical representation of the various loopback configurations with the associated
GNLB commands shown. Table 22 on page 56 for a description of these commands.
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 toward the H2TU-C and verify that the returned (looped) signal
to the test set is error-free.
3 If Step 2 fails, have the CO tester transmit the (3-in-5) in-band loopdown code.
4 Have the CO tester send the NLOC (4-in-7) in-band loopup for 5 seconds. You should be able to observe the
NLOC message on the front-panel display. The Status LED on the front panel should be yellow, and the
loopback mode should also be identified on the Monitor screen.
5 Repeat Step 2 . If the test passes, the problem is in the downstream direction. If it fails, the problem is in the
upstream direction.
The equalizer settings only apply to the specific DSX-1 port selected by the ADS1 option, MUX
or AUX. The unselected port defaults to an equalizer setting of zero.