Appendix B - Technical Reference
150-458-100-05
22
February 23, 2000
HRE-458 List 1, List 1B, and List 2
Figure 9.
HRE-458 with Cover Removed
Lightning Protection Unit (LPU)
The LPU, shown in
, is a printed circuit board assembly that attaches to the card-edge
connector of each slot. The LPU is used primarily for protecting the HDSL loops from lightning activity. All
HRE-458 units come equipped with ten LPUs.
Each LPU contains four gas tubes which provide surge protection to each of the slots’ four ports. The tubes have
three leads which provide protection from Tip and Ring to ground. The ground pin is connected to pin 1 of each
slot. The gas tube parameters are equivalent to a TII 47 BT. The dc breakdown ranges from 300 to 500 volts. The
tube can withstand at least 400, 10/1000, and 500 amp discharges. Although the individual gas tubes are field-
replaceable components, ADC recommends replacing the entire LPU when any of its protector tubes are suspected
of functioning improperly. (See
“Appendix A - Specifications” on page 19
for details on replacing an LPU.
Front view
Retaining bar
wingnut
Knobbed
retainer screw
Card cage
(four mounting
positions)
Ribbon cage
ground cable
Retainer bar
Rear view
Braided stub
shield ground wire
Top View
Retaining bar wingnuts
Retaining bar
Slots 1-4
1
5
2
9
10
6
3
7
4
8
Slots 5-8
Retaining bar
Retaining bar wingnuts
Slot 10
Slot 9
