Section 150-319-124
Revision 03
Page 14
B. APPLICATIONS WITHOUT HIGAIN
DOUBLERS (HDU-451)
12. SECTION INTRODUCTION
12.01
This section addresses HLU-319, List 2D
operation without the use of doublers. For
applications without doublers, the HLU-319 is directly
connected to the HRU-412 by the two cable pairs.
13. POWER CONSUMPTION
13.01
The three most important power demands of
an HLU-319, List 2D on the shelf power supply are its
maximum power consumption, its maximum power
dissipation, and its maximum current drain. These
three parameters for the HLU-319, List 2D, on a per-
slot and per-shelf basis, are as follows:
Maximum Power Dissipation:
•
Per Slot = 7 Watts
•
Per Shelf = 196 Watts
Maximum Power Consumption:
•
Per Slot = 16 Watts
•
Per Shelf = 448 Watts
Maximum Current Drain:
•
Per Slot = 0.38 Amps
•
Per Shelf = 10.5 Amps
Note: The worst case conditions, under which these
parameters were measured, include a 9,000
ft., AWG 26 loop, 60 mA of Customer
Provided Equipment (CPE) current, a fully
loaded 28-slot shelf, and a -42.5 V shelf
battery voltage with the HLU-319 4-character
display “OFF.” For the purpose of
comparison, the HLU-319, List 1 unit
dissipates 8.5 Watts and consumes 18 Watts
per slot under similar worst case conditions.
13.02
The Maximum Power Dissipation measures
the power that is converted into heat buildup within
the unit. It contributes to the total heat generated in
the space around the unit. It is used to determine the
maximum number of fully loaded shelves per bay that
does not exceed the maximum allowable power
dissipation density in Watts/sq. ft.
13.03
In Central Office locations, the maximum
power dissipation for open-faced, natural convection
cooled mountings is limited to 120 Watts/sq. ft. per
Section 4.2.3 of the NEBS standard TR-NWT-000063.
The footprint of a standard 28-slot 23-inch HLU-319,
List 2D shelf is 7.024 sq. ft. Thus, the maximum bay
dissipation is limited to 840 Watts. At 7 Watts per
slot, this limits the number of occupied slots to 120
per bay.
13.04
The thermal loading limitations, imposed
when using the HLU-319, List 2D in a Controlled
Environmental Vault (CEV) or other enclosures, are
determined by applying the HLU-319, List 2D's power
parameters to the manufacturer's requirements for
each specific housing.
13.05
The Maximum Power Consumption is the total
power that the HLU-319, List 2D consumes or draws
from its -48 V shelf power source. This parameter is
needed when the HLU-319 is remotely located to its
serving CO. It determines the battery capacity
required to maintain an 8-hour standby battery
reserve for emergency situations; thus limiting the
maximum number of plugs per line unit’s remote
enclosure. Use the above data to perform this
analysis on a case-by-case basis.
13.06
The Maximum Current Drain is the maximum
current drawn from the shelf power supply when it is
at its minimum voltage (-42.5 V). It determines the
shelf fusing requirements. All HLU-319 shelves are
partitioned into two equal halves, each fused at 10
amps for a total of 20 amps per shelf. A fully loaded
shelf draws 10.5 amps worst case. This is within the
20 amp fuse limit.
13.07
Heat baffles should be placed between every
other shelf, in racks containing more than two shelves.
This technique deflects the rack’s heat outward and
reduces thermal stress on the plugs.
14. LOOPBACK OPERATION
14.01
The HiGain system has a family of loopback
options. The most important of these is the “Smart-
Jack” loopback which enables the HRU-412 to respond
to the standard (2/3 in 5) Smart-Jack in-band loopback
codes, and thus emulates the functions of a standard
Network Interface Device (NID). This option can be
ENAbled or DISabled from either the front panel
buttons or the terminal System Settings Menu.
