Overview
150-454-111-06
4
February 25, 2000
HRE-454
Doubler Applications
The HRE-454 houses the following HiGain doubler units:
•
HDU-404 T1 (1.544 Mbps)
•
HDU-451 T1 (1.544 Mbps)
•
EDU-451 E1 (2.048 Mbps)
All three units have identical pin assignments as shown in
. The wire list for each doubler
appears in
summarizes all the HRE-454 interfaces.
F
UNCTIONAL
D
ESCRIPTION
The following section discusses the function of each component on the HRE-454.
The HRE-454 consists of a metal alloy card cage with space for up to four remote or doubler units, a stainless steel
composite baseplate, and a stainless steel cover which maintains weather-tight integrity.
show the details for each unit.
Gel-filled Stub Units
The gel-filled unit comes equipped with three metal valves installed in the base section, as shown in
. The gel-filled, screened, 28-pair, 24 American Wire Gauge (AWG) cable stub on the gel-filled unit is
equivalent to an ALP FTS-PIC filled core telephone cable. (Refer to
for a complete description
of the cable stub.) The unit has foam skin insulation with a single-filled jacket. This insulation allows the cable
stub on the gel-filled unit to be used in buried, aerial, and duct applications. Standard color codes are used for pair
identification with color compounds chosen for electrical balance and permanency. The outer jacket provides a
flexible protective covering that withstands exposure to sunlight, atmospheric temperatures, ground chemicals,
and stresses expected in standard installations. The outside diameter of the cable is 0.64 inches (16.25 mm).
The gel-filled unit is similar to the air-filled unit (
), except that the gel-filled unit has a breather
vent valve instead of a pressure relief valve. The breather vent valve allows the circulation of outside air through
the gel-filled enclosure. Circulating outside air through the gel-filled enclosure prevents the buildup of excessive
moisture and other damaging contaminants within the enclosure.
A combined Schrader air stem/external air input T-valve is also included with the gel units. The Schrader air stem
valve can be used to connect to an external air source or to release the internal pressure whenever the dome is to
be removed. Opposite the Schrader valve, the external air input valve accepts tubing for connection to an external
air source. The pressure cutoff valve allows the external source of air to be cut off when the dome is to be opened.
An optional pressure relief valve is included in the shipping kit for the gel units. The kit comes in a small plastic
bag that is attached to the shrink tab on one of the spare pairs. Use the valve in place of the breather vent valve
when the get unit is to be locally pressurized.
The cable complies with the requirements of the American National Standards Institute
(ANSI) and the Insulated Cable Engineers Association (ICEA) S-84-608-1994 and REA
PE-89, respectively.
