Revision 01
March 31, 1998
150-412-181-01
12
PairGain Engineering - Plant Series
HRU-412 List 8A
Local and Line Powering
The HRU-412 List 8A unit can be line powered or local powered. It always
chooses the local -48 Vdc power source, if present. It defaults to line power
only in the absence of local power. Some older HLUs automatically turn off
their line powering when connected to the HRU-412 List 8A. The older
versions of the HLU-231 (Lists 1, 2, 3, 3A, and 4) must have their PWRF user
option disabled for them to work properly with a locally powered HRU-412
List 8A. Refer to the appropriate HLU technical practice if you need more
information about its local and line powering capabilities.
When locally powered, the HRU-412 List 8A provides 15 mA (short loop) to
10 mA (long loop) simplex sealing current toward all versions of the HLU
over the two HDSL pairs. JP2, shown in Figure 3, allows the sealing current
to be enabled or disabled. To enable the sealing current, connect JP2 across
both terminals. To disable the sealing current, remove the jumper from the
inner terminal and attach it to the outer terminal. The factory default setting
is disabled. This simplexed sealing current is polarity sensitive and will not
flow if the HDSL loops at the HRU-412 List 8A are reversed. Reversed loops
are indicated by a CHREV message in the ALARMS line of the Span Status
screen.
The simplex sealing current is not compatible with doublers HDU-451 List 1,
2, or 3. These doublers block the flow of simplex sealing current. To allow
the flow of sealing current, use doublers HDU-451 List 4, HDU-439,
HDU-437, or HDU-409 with the HRU-412 List 8A.
JP2
Allows the enabling or disabling of the sealing current. To enable,
connect JP2 across both terminals. To disable (default), remove
the jumper from the inner terminal and leave it attached to the
outer terminal only.
Table 3.
Rear Panel Components (Cont.)
Summary of Contents for 150-1103-81
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