363-206-305
Power
4-6
Issue 3 June 2000
Wideband Shelf Transmission Circuit Packs
4
OLIU Circuit Packs
4
The OLIU circuit packs are powered by two DC-to-DC converters located on the
circuit packs. The backplane power feeders supply A and B
−
48 volts to these
converters via diode ORed circuits and are fuse-mounted on each of the circuit
packs. One converter supplies +5 volts and the other supplies
−
5.2 volts.
DS1/DS1PM Circuit Packs
4
The DS1/DS1PM circuit packs receive +5 volt power via backplane connections
from the both OLIU 26G2-U circuit packs in the Main slots. Power selector circuits
(diode ORed) and fuses for the +5 volts are located on the DS1/DS1PM circuit
packs. The fuses on the DS1/DS1PM circuit packs protect the backplane and
prevent DS1/DS1PM unit failures from affecting service in the other DS1 units.
Control Circuit Packs
4
The SYSCTL circuit pack is powered by a
−
48 volt to +5 volt DC-to-DC converter
located on the pack. The backplane power feeders supply A and B
−
48 volts to
these converters via diode ORed circuits and fuses mounted on the circuit packs.
Narrowband Shelf –48 V Battery
Powering
4
The PCU in the DDM-2000 FiberReach narrowband shelf provides fusing and
converts a –48 V DC input power feed to voltages required for the other circuit
packs in the narrowband shelf. Figure 4-5 shows the power distribution. The
narrowband shelf can draw up to 84 watts of power and meets all performance
requirements when the DC input voltage varies between –42.5 V and –56.5 V, as
specified in TR-499.
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