PairGain T1L2BZ0A, Manual, Page: 19 / 76

150-231-184-05, Revision 05 Installation
HLU-231 List 8D October 25, 1999 9
V
ERIFICATION
Once the HLU-231 is installed, verify that it is operating properly by monitoring the:
• Status LED
• Status messages reported by the front panel display (see Table 2 on page 6 ).
Verification without a Downstream Device
If there is no downstream device installed:
1 Verify that the HLU powers up. (The front panel display illuminates and reports four-character status
messages. See
Table 2 on page 6 for a list of messages.)
2 Verify that the HLU attempts to communicate with downstream devices. Even if a downstream device is not
present, the following events should occur:
a The front panel display reports four-character status messages.
b The HLU enters self-test mode (Status LED is yellow).
c The HLU again attempts communication with downstream devices, repeating events a through b until a
downstream device is successfully detected.
Verification with a Downstream Device
If a downstream device has been installed:
1 Verify that the HLU powers up. (The front panel display illuminates and reports status messages.)
2 Verify that the HLU attempts to communicate with downstream devices (status LED flashes green). One of
the following occurs:
a If downstream devices are successfully identified and the HDSL loops synchronize, the HLU status LED
will be a steady green. The HLU reports normal margin messages on the front panel display.
b If downstream devices are not successfully identified, the HLU reports four-character status messages
and enters self-test mode. The HLU successively:
– Enters self-test mode.
– Completes self-test mode.
– Attempts communication again.
– Reports four-character status messages.
The HLU repeats this cycle until a downstream device is detected.
3 If there is more than one span, verify that each subsequent span synchronizes normally by monitoring the
front panel display messages.
4 If a remote unit is installed, verify that the last span synchronizes normally. The HLU status LED should be
a steady green, and the front panel display reports normal margin messages.
5 Verify that a valid T1 signal has been applied to the HLU and the HRU.
a If no T1 signal is being applied to either the HLU or the HRU inputs, then the appropriate T1 alarms
(LLOS or RLOS) are displayed on the front panel and the status LED flashes red.
b If a valid T1 signal is being supplied to the HLU and HRU, then T1 alarm indications should be absent
and the status LED should be a steady green.