Installation
150-402-102-01, Revision 01
12
July 27, 1998
HRU-402 List 2
I
NSTALLATION
T
EST
Testing of your HiGain system allows you to verify the integrity of the HDSL
channels to the HLU as well as the DS1 channels to the customer and the
HLU DSX-1 interface. While the HRU-402 List 2 displays system condition
messages at the Remote and Maintenance Terminals, and by color-coded
LED displays on the front panel, the HLU displays system conditions by
four-character LCD messages. To facilitate test messaging with CO test
personnel, four-character, front-panel messages for the HLU-231 List 8 are
provided in
.
To test the loopbacks:
1
Press the loopback (LBK) button on the remote unit front panel for at
least five seconds (see
for the location of this button).
2
Verify that the Yellow HRU front panel LBK LED turns on, indicating
that the HRU is in its digital (NREM) loopback state. Also verify, if
possible, that the HLU displays the message NREM, which also
indicates that the HRU-402 List 2 is in loopback.
3
Have the CO tester transmit a T1 test signal into the HLU and measure
that the returned (looped) signal is error free.
4
If the above test fails, remove the remote unit from its loopback state by
again pressing the loopback button for five seconds. Verify that the LBK
is off.
5
Have the CO tester send the HLU (4 in 7) in-band loop-up (NLOC) for
five seconds. Verify that the HLU displays the message NLOC
indicating that the HLU unit is in its network loopback state.
6
Repeat Step 3. If the test passes, the problem is in the cable pair or the
HRU-402 List 2. If it fails, the problem is at the CO.
7
If the sealing current option is enabled, insert a milliampmeter in series
with the Tip or Ring of either HDSL pair and verify that approximately
10 mA of sealing current is flowing in either conduction (approximately
20 mA total).
If you encounter trouble at the T1 interface, verify that the unit
is making a positive connection with the mounting assembly
connector.
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