150-458-100-05
Appendix B - Technical Reference
HRE-458 List 1, List 1B, and List 2
February 23, 2000
25
Spare Connections
The HRE-458 stub has 11 spare pairs and one order wire pair. Each stub group has two spare pairs. The other three
spare pairs and order wire pairs are located in the Inner Statial (IS) group. All of these spare pairs are located in
the IS group and are folded back for easy access if needed.
Order Wire Connections
The access port for the external order wire pair is connected to its surge protector by the black and white jumper
wire. The black and white order wire pairs also terminate on this protector. This permits access to the order wire
without opening the enclosure. Simply unscrew the order wire protective cap (see
) to expose
the order wire terminals.
General Deployment Rules
The HRE-458 is an airtight enclosure. The environment surrounding the enclosure traps the heat generated by the
installed units and, in effect, causes a significant rise in temperature within the enclosure. The number of doublers
or repeaters that can be reliably housed in the HRE-458 is a function of each plug type, doubler version, and solar
exposure (see
for a list of the HRE-458 deployment rules).
•
Even when the deployment rules are followed, the metal surfaces of the installed units can feel hot to the touch
when removed from an HRE-458 that is operating in elevated ambient temperatures. These conditions are
normal for the plugs operating under these circumstances.
•
When less than ten slots are being used at initial turnup, assign the slots in the following sequence to reduce
the hot spot temperature (10, 9, 1, 5, 4, 8, 2, 6, 3, 7).
In order to comply with the requirements in TA-NWT-0012101 (maximum ambient temperature of 115 °F with
full solar load), the number of full T1 HDU-439 or HDU-437 doublers must be limited to eight without full solar
load or six with full solar load. The fractional doublers, HDU-219 and HDU-217, and the full T1 microdoublers,
HDU-409 and HDU-407, comply with the TA when all ten slots are occupied with full solar load.
When mixing HDU-437 and HDU-439 doublers with HDU-217, HDU-219, HDU-409, and HDU-407 doublers,
use the HDU-437 and HDU-439 deployment rules for all the doublers. When mixing 239T1, ISDN, or DDS
repeaters with HiGain doublers in this enclosure, assign a thermal load of one-fourth the load of the doubler to the
239T1 repeater and one-half the thermal load of a doubler to the DDS/IDSN repeaters.
Four T1 repeaters and two DDS ISDN repeaters are thermally equivalent to one HDU-439 or one
HDU-409 doubler.
