December 22, 1997
Section 150-219-100-02
HDU-217/219 and
HCC-239 List
1
Page 19
SYSTEM ADMINISTRATION
Fault Isolation
Solutions for common problems are listed in Table 7. For additional
help, refer to Figure 5.
Table 7. Fault Isolation Guide
Problem
Solution
LED does not light
1 Verify that the HLU is installed and operational
in the central office (CO).
2 Verify proper cabling between the doubler
enclosure and the central office.
3 Measure 100 V to 200 Vdc between pins 5 or 6
and 8 or 9. This voltage peaks every 15 seconds
as the HLU powers up. If less than 130 Vdc is
present, check the cabling or the HLU. Only the
line units mentioned in this practice can be used
to power doublers. Other HLU versions can
seem to work but do not provide reliable
operation and should not be used.
HDSL LED continues to
flash green once a second
Synchronization is being attempted with the
upstream unit.
HDU-217 or HDU-219
loses power
The HLU at the CO is not present. Measure the
resistance of the HDSL input loop. Resistance
should be normal loop resistance plus the 25-Ohm
signature of the HLU.
