150-506-100-03
Appendix B: Additional Information
HRE-506 List 1 and List 2
March 28, 2000
27
Lightning Protection Unit
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 and customer T1 circuits.
All HRE-506 units are equipped with four LPUs. Each LPU contains four gas tubes that provide surge protection
to the four ports in each slot. The tubes have three leads that 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 Vdc breakdown ranges from 300 to 500 volts. The
tube can withstand at least 400, 10/1000, 500 amp discharges. Amp discharges are quantities of discharges that
occur before system degradation.
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.
Figure 12.
Lightning Protection Unit
