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Applications
L
OCAL AND
The HRU-419 unit can be line or local powered. The unit always uses the
local -48 V power source if it is present, and defaults to line power in the
absence of local power. List 6 and higher versions of the HLU-231, and all
versions of the HLU-319 and HLU-388, and versions 6.4 and above of the
HLU-231 List 1, 2, 3, 3A and 4 units automatically turn off their line power
supply when connected to a locally powered HRU-419. The earlier versions
of the HLU-231 (Lists 1, 2, 3, 3A and 4) must first have their PWRF user
option set to disable to work properly with a locally powered HRU-419.
When locally powered, the HRU-419 also provides from 20 mA (long loop)
to 30 mA (short loop) of simplex sealing current towards all versions of the
HLU over the 2 HDSL pairs. Jumper JP1, shown in
allows the sealing current to be enabled or disabled
(see"The HRU-419 Circuit Board" on page
This simplexed sealing current is polarity sensitive and will
not flow if the two HDSL loops adjacent to the HRU are
reversed.
Reversed loops are indicated by a CHREV message in the "Alarms" field of
the Span Status screen shown in
The simplex sealing current is not compatible with the List 1, 2, or 3
HDU-451 doublers. These doublers block the flow of simplexed sealing
current. The HDU-451 List 4, the HDU-437 or the HDU-439 must be used
with the HRU-419 to provide a path through which the simplexed sealing
current can flow.
If local power is lost to the HRU in a non-doubler or a single doubler circuit,
the system will lose sync. When the HLU or HDU attempts to re-acquire
sync, it will detect that the HRU is not locally powered and apply line power
to it.
10
L
P
INE
OWERING
"View Span Status" on page
September 25, 1998
Figure 7 on page
16).
150-419-100-03>
17,
24.
HRU-419 List 1
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